Explosions and fires ripped through an ammunition depot in Russian-occupied Crimea on Tuesday in the second suspected Ukrainian attack on the peninsula in just over a week, forcing the evacuation of more than 3,000 people. Russia blamed the blasts in the village of Mayskoye on an “act of sabotage,” without naming the perpetrators. Separately, the Russian business newspaper Kommersant quoted residents as saying plumes of black smoke also rose over an air base in Crimea’s Gvardeyskoye. Ukraine stopped short of publicly claiming responsibility for any of the blasts, including those that destroyed nine Russian planes at another Crimean air base last week. Russia seized the Crimean Peninsula in 2014 and has used it to launch attacks against Ukraine in the war that began nearly six months ago. If Ukrainian forces were behind the explosions, that would represent a significant escalation in the war. Such attacks could also indicate that Ukrainian operatives are able to penetrate deeply into Russian-occupied territory. Ukrainian President Volodymyr Zelenskyy alluded to Ukrainian attacks behind enemy lines when he included individuals “who oppose the occupiers in their rear” in a list of people he thanked for supporting the country’s war effort. In a video address Tuesday night, he also warned people not go near Russian military installations and storage sites for ammunition and equipment. Read: Iran submits a ‘written response’ in nuclear deal talks In another reported act of sabotage, Russia’s Tass news service quoted the FSB security agency as saying Ukrainian operatives blew up six high-voltage transmission towers earlier this month in Russia’s Kursk region, close to Ukraine. The Kremlin has demanded that Kyiv recognize Crimea as part of Russia as a condition for ending the fighting, while Ukraine has vowed to drive Moscow’s forces from the peninsula on the Black Sea. Videos posted on social media showed thick columns of smoke rising over raging flames in Mayskoye, and a series of explosions could be heard. The Russian Defense Ministry said a power plant, electrical lines, railroad tracks and apartment buildings were damaged. “We came out to take a look and saw clouds of smoke coming from the cowshed where the military warehouses are,” said resident Maksim Moldovskiy. “We stayed there until about 7-8 a.m. Everything was exploding — flashes, fragments, debris falling on us. Then the emergency guys came and said they were evacuating everybody.” Crimea’s regional leader, Sergei Aksyonov, said two people were injured and more than 3,000 evacuated from two villages. “The detonations are rather strong. Ammunition is strewn all over the ground,” he said, adding that several homes burned down. In what may have been retaliation for the attacks in Crimea, Russian warplanes fired missiles at a military airfield in Zhytomyr, 87 miles (140 kilometers) west of Kyiv, damaging a runway and vehicles, Ukrainian officials reported. Crimea is a popular summer destination for Russian tourists, and last week’s explosions at Crimea’s Saki air base sent sunbathers on beaches fleeing as flames and pillars of smoke rose over the horizon. Ukrainian officials warned Tuesday that Crimea would not be spared the ravages of war. Rather than a travel destination, “Crimea occupied by Russians is about warehouse explosions and a high risk of death for invaders and thieves,” Ukrainian presidential adviser Mykhailo Podolyak said on Twitter. Read: Western states hit with more cuts to Colorado River water Russia blamed last week’s explosions on an accidental detonation of munitions, but satellite photos and other evidence — including the dispersed blast sites — pointed to a Ukrainian attack, perhaps with anti-ship missiles, military analysts said. Britain’s Defense Ministry said in an intelligence update that vessels in Russia’s Black Sea Fleet are in an “extremely defensive posture” in the waters off Crimea, with ships barely venturing out of sight of the coastline. Russia’s flagship Moskva went down in the Black Sea in April, and last month Ukrainian forces retook strategic Snake Island. The Russian fleet’s “limited effectiveness undermines Russia’s overall invasion strategy,” the British said. “This means Ukraine can divert resources to press Russian ground forces elsewhere.” Russian Defense Minister Sergei Shoigu charged that in addition to supplying arms to Ukraine, Western allies have provided detailed intelligence and instructors to help Ukraine operate weapons that can hit deep in occupied territory. “Western intelligence agencies not only have provided target coordinates for launching strikes, but Western specialists also have overseen the input of those data into weapons systems,” Shoigu said. In other developments: — A U.N.-chartered ship loaded with Ukrainian grain set out for the hunger-stricken Horn of Africa in the first such relief delivery of the war. The shipment was made possible by an internationally brokered deal to free up grain trapped in Ukrainian ports by the fighting and establish safe corridors through the mined water of the Black Sea. — U.N. Secretary-General Antonio Guterres plans to travel to Ukraine for a meeting Thursday in the western city of Lviv with Zelenskyy and Turkey’s President Recep Tayyip Erdogan. They are expected to discuss the grain shipments and a possible fact-finding mission to the Russian-controlled Zaporizhzhia nuclear power plant, which Russia and Ukraine have accused each other of shelling. Guterres will also visit Odesa on Friday. During Guterres’ last trip to Ukraine, in April, Russia forces launched an airstrike on Kyiv while he was visiting the capital. — Samantha Power, head of the U.S. Agency for International Development, said the United States is giving more than $68 million in additional funding to the U.N. World Food Program “to purchase, move, and store up to 150,000 metric tons of Ukrainian wheat to help respond to the global food crisis.” — Russian shelling killed at least two civilians in the industrial Donbas region in the east and in the city of Kharkiv in the northeast, Ukrainian authorities said.

Russian forces suffered heavy losses in a Ukrainian attack that destroyed a pontoon bridge they were using to try to cross a river in the east, Ukrainian and British officials said in another sign of Moscow’s struggle to salvage a war gone awry. Ukrainian authorities, meanwhile, opened the first war crimes trial of the conflict Friday. The defendant, a captured Russian soldier, stands accused of shooting to death a 62-year-old civilian in the early days of the war. The trial got underway as Russia’s offensive in the Donbas, Ukraine’s eastern industrial heartland, seemed to turn increasingly into a grinding war of attrition. Ukraine’s airborne command released photos and video of what it said was a damaged Russian pontoon bridge over the Siversky Donets River in Bilohorivka and several destroyed or damaged Russian military vehicles nearby — the Ukrainians said they destroyed at least 73 tanks and other military equipment during the two-day battle earlier this week. The command said its troops “drowned the Russian occupiers.” Britain’s Defense Ministry said Russia lost “significant armored maneuver elements” of at least one battalion tactical group in the attack. A Russian battalion tactical group consists of about 1,000 troops. “Conducting river crossings in a contested environment is a highly risky maneuver and speaks to the pressure the Russian commanders are under to make progress in their operations in eastern Ukraine,” the ministry said in its daily intelligence update. In other developments, a move by Finland and, potentially, Sweden to join NATO was thrown into question when Turkish President Recep Tayyip Erdogan said his country is “not of a favorable opinion” toward the idea. He accused Sweden and other Scandinavian countries of supporting Kurdish militants and others Turkey considers terrorists. Also Read: Russian pipeline sanctions raise fears of gas interruption Erdogan did not say outright that he would block the two nations from joining NATO. But the military alliance makes its decisions by consensus, meaning that each of its 30 member countries has a veto over who can join. An expansion of NATO would be a blow to Russian President Vladimir Putin, who undertook the war in what he said was a bid to thwart the alliance’s eastward advance. But in the wake of the invasion of Ukraine, other countries along Russia’s flank fear they could be next. With Ukraine pleading for more arms to fend off the invasion, the European Union’s foreign affairs chief announced plans to give Kyiv an additional 500 million euros ($520 million) to buy heavy weapons. Ukrainian Defense Minister Oleksii Reznikov welcomed the heavy weapons making their way to the front lines but admitted there is no quick end to the war in sight. “We are entering a new, long-term phase of the war,” he wrote in a Facebook post. “Extremely difficult weeks await us. How many there will be? No one can say for sure.” The battle for the Donbas has turned into a village-by-village, back-and-forth slog with no major breakthroughs on either side and little ground gained. In his nightly address Friday, Ukrainian President Volodymyr Zelenskyy said no one can predict how long the war will last but that his country’s forces have been making progress, including retaking six Ukrainian towns or villages in the past day. Fierce fighting has been taking place on the Siversky Donets River near the city of Severodonetsk, said Oleh Zhdanov, an independent Ukrainian military analyst. The Ukrainian military has launched counterattacks but has failed to halt Russia’s advance, he said. “The fate of a large portion of the Ukrainian army is being decided — there are about 40,000 Ukrainian soldiers,” he said. The Ukrainian military chief for the Luhansk region of the Donbas said Friday that Russian forces opened fire 31 times on residential areas the day before, destroying dozens of homes, notably in Hirske and Popasnianska villages. He said Russian troops have taken nearly full control of Rubizhne, a city with a prewar population of around 55,000. In the ruined southern port of Mariupol, Ukrainian fighters holed up in a steel plant faced continued Russian attacks on the last stronghold of resistance in the city. Sviatoslav Palamar, deputy commander of Ukraine’s Azov Regiment, said his troops will hold out “as long as they can” despite shortages of ammunition, food, water and medicine. Justin Crump, a former British tank commander who is now a security consultant, said Moscow’s losses have forced it to downsize its objectives in Ukraine. He said the Russians have had to use hastily patched-together units that haven’t trained together. “This is not going to be quick. So we’re settled in for a summer of fighting at least. I think the Russian side is very clear that this is going to take a long time,” he said. In the first war crimes case brought to trial, Russian Sgt. Vadim Shyshimarin, 21, could get life in prison if convicted of shooting a Ukrainian man in the head through an open car window in a village in the northeastern Sumy region on Feb. 28, four days into the invasion. Ukrainian Prosecutor General Iryna Venediktova said she is readying war crimes cases against 41 Russian soldiers for offenses including bombing civilian infrastructure, killing civilians, rape and looting. It was not immediately clear how many of the suspects are in Ukrainian hands and how many would be tried in absentia. In a small Kyiv courtroom, scores of journalists witnessed the start of the wartime proceedings, which will be closely watched by international observers to make sure the trial is fair. The defendant, dressed in a blue and gray hoodie and gray sweatpants, sat in a small glass cage during the proceedings, which lasted about 15 minutes and will resume on Wednesday. Shyshimarin was asked a series of questions, including whether he understood his rights and whether he wanted a jury trial. He declined the latter. His Ukraine-assigned attorney, Victor Ovsyanikov, has acknowledged that the case against Shyshimarin is strong and has not indicated what the soldier’s defense will be. Shyshimarin, a member of a tank unit that was captured by Ukrainian forces, admitted that he shot the civilian in a video posted by the Security Service of Ukraine, saying he was ordered to do so. As the war grinds on, teachers are trying to restore some sense of normalcy after the fighting shuttered Ukraine’s schools and upended the lives of millions of children. In Kharkiv, Ukraine’s second-largest city, lessons are being given in a subway station that has become home for many families. Children joined their teacher Valeriy Leiko around a table to learn about history and art, with youngsters’ drawings lining the walls. “It helps to support them mentally. Because now there is a war, and many lost their homes. ... Some people’s parents are fighting now,” Leiko said. In part because of the lessons, he said, “they feel that someone loves them.” An older student, Anna Fedoryaka, monitored a professor’s online lectures on Ukrainian literature, admitting: “It is hard to concentrate when you have to do your homework with explosions by your window.”