Russian forces have installed multiple rocket launchers at Ukraine's shut-down Zaporizhzhia nuclear power plant, Ukrainian officials claimed Thursday, raising fears Europe's largest atomic power station could be used as a base to fire on Ukrainian territory and heightening radiation dangers. Ukraine's nuclear company Energoatom said in a statement that Russian forces occupying the plant have placed several Grad multiple rocket launchers near one of its six nuclear reactors. It said the offensive systems are located at new “protective structures” the Russians secretly built, "violating all conditions for nuclear and radiation safety.” The claim could not be independently verified. The Soviet-built multiple rocket launchers are capable of firing rockets at ranges of up to 40 kilometers (25 miles), and Energoatom said they could enable Russian forces to hit the opposite bank of the Dnieper River, where each side blames the other for almost daily shelling in the cities of Nikopol and Marhanets. The plant is in a southern Ukrainian region the Kremlin has illegally annexed. The Zaporizhzhia station has been under Russian control since the war’s early days. Russia and Ukraine accuse each other of shelling the plant and risking a radiation release. Although the risk of a nuclear meltdown is greatly reduced because all six reactors have been shut down, experts have said a dangerous radiation release is still possible. The reactors were shut down because the fighting kept knocking out external power supplies needed to run the reactors' cooling systems and other safety systems. Read more: Ukraine leader defiant as drone strikes hit Russia again The U.N.'s nuclear watchdog, the International Atomic Energy Agency, has stationed inspectors at the plant and has been trying to persuade both sides in the conflict to agree to a demilitarized zone around it. The agency did not immediately respond to a request for comment about the reported Grad installation. Ukraine has accused the Russians before of having heavy weapons at the plant. The Kremlin has said it needs to maintain control of the plant to defend it from alleged Ukrainian attacks. With renewed focus on the dangers at Zaporizhzhia in the war, dragging on past nine months, the Kremlin is sending new signals about how to end it. It said Thursday it’s up to Ukraine’s president to end the military conflict, suggesting terms that Kyiv has repeatedly rejected, while Russian President Vladimir Putin vowed to press on with the fighting despite Western criticism. Kremlin spokesman Dmitry Peskov said that "(Ukrainian President Volodymyr) Zelenskyy knows when it may end. It may end tomorrow if he wishes so.” The Ukraine war has deteriorated relations between Russia and much of the rest of the world, but limited cooperation continues in some areas, such as exchanges of prisoners. On Thursday, in a dramatic swap that had been in the making for months, Russia freed American basketball star Brittney Griner while the United States released a jailed Russian arms dealer. The Kremlin has long said that Ukraine must accept Russian conditions to end the fighting. It has demanded that Kyiv recognize Crimea — a Ukrainian peninsula that Moscow illegally annexed in 2014 — as part of Russia and also accept Moscow’s other land gains in Ukraine. Zelenskyy and other Ukrainian officials have repeatedly rejected those conditions, saying the war will end when the occupied territories are retaken or Russian forces leave them. In an acknowledgement that it’s taking longer than he expected to achieve his goals in the conflict, Putin said Wednesday that the fighting in Ukraine “could be a lengthy process” while describing Moscow's land gains as “a significant result for Russia." During a conference call with reporters, Peskov said Moscow wasn’t aiming to grab new land but will try to regain control of areas in Ukraine from which it withdrew just weeks after incorporating them into Russia in hastily called referendums — which Ukraine and the West reject as illegal shams. After earlier retreats from the Kyiv and Kharkiv areas, Russian troops last month left the city of Kherson and parts of the Kherson region, one of the four illegally annexed Ukrainian regions. Read more: Russian airfield hit, a day after drone strikes on bases Putin vowed Thursday to achieve the declared goals in Ukraine regardless of the Western reaction. “All we have to do is make a move and there is a lot of noise, chatter and outcry all across the universe. It will not stop us fulfilling combat tasks,” Putin said. He described Russian strikes on Ukraine’s energy facilities and other key infrastructure as a legitimate response to an Oct. 8 truck bombing of a key bridge linking Crimea with Russia’s mainland, and other attacks the Kremlin claimed Ukraine carried out. Putin also cited Ukraine’s move to halt water supplies to the areas in eastern Ukraine that Russia controlled. “There is a lot of noise now about our strikes on the energy infrastructure,” Putin said at a meeting with soldiers whom he decorated with the country’s top medals. “Yes, we are doing it. But who started it? Who struck the Crimean bridge? Who blew up power lines from the Kursk nuclear power station? Who is not supplying water to Donetsk?” While stopping short of publicly claiming credit for the attacks, Ukrainian officials welcome their results and hint at Ukrainian involvement. Heavy fighting continues, mostly in regions Russia annexed. Zelenskyy's office said 11 civilians were killed in Ukraine Wednesday. The Donetsk region has been the epicenter of the recent fighting. Russian artillery struck the town of Yampil during distribution of humanitarian aid to civilians, Ukrainian officials said. Buildings were damaged in Kurakhove, 35 kilometers (22 miles) west of the regional capital, Donetsk, officials said. More than ten cities and villages in the region were shelled, including the town of Bakhmut, which has remained in Ukrainian hands despite Moscow’s goal of capturing the entire annexed Donbas region bordering Russia.

A U.N. inspection team entered Ukraine's Zaporizhzhia nuclear power plant Thursday on a mission to safeguard it against catastrophe, reaching the site amid fighting between Russian and Ukrainian forces that prompted the shutdown of one reactor and underscored the urgency of the task. The 14-member delegation from the International Atomic Energy Agency arrived in a convoy of SUVs and vans after months of negotiations to enable the experts to pass through the front lines and get inside Europe's biggest nuclear plant. “The IAEA is now there at the plant and it’s not moving. It’s going to stay there. We’re going to have a continued presence there at the plant with some of my experts,” IAEA director Rafael Grossi, the mission leader, declared after the group got its first look at conditions inside. Also read: UN inspectors head to Ukraine nuclear plant in war zone But he added: “I will continue to be worried about the plant until we have a situation which is more stable." As the experts made their way through the war zone toward the complex, Russia and Ukraine accused each other of shelling the area and trying to derail the visit. The fighting delayed the team’s progress. “There were moments when fire was obvious — heavy machine guns, artillery, mortars at two or three times were really very concerning, I would say, for all of us," Grossi said. Just before the IAEA team arrived, Energoatom, Ukraine’s state nuclear power company, said Russian mortar shelling had led to the shutdown of one of its reactors by its emergency protection system and had damaged a backup power supply line used for in-house needs. Also read: Eyes on Kherson as Ukraine claims bold move on Russians One of the plant’s reactors that wasn’t operating was switched to diesel generators, Energoatom said. Once inside the plant, Grossi said, his experts were able to tour the entire site, including control rooms, emergency systems and diesel generators. He said he met with the plant's staff and residents of the nearby village, Energodar, who asked him for help from the agency. He reported that the team had collected important information in its initial inspection and will remain there to continue its assessment. “It is obvious that the plant and the physical integrity of the plant has been violated several times by chance, deliberately — we don’t have the elements to assess that," Grossi said. “And this is why we are trying to put in place certain mechanisms and the presence, as I said, of our people there.” The Zaporizhzhia plant has been occupied by Russian forces but run by Ukrainian engineers since the early days of the 6-month-old war. Ukraine alleges Russia is using it as a shield to launch attacks, while Moscow accuses Ukraine of recklessly firing on the area. Ukrainian President Volodymyr Zelenskyy had tough words for the IAEA delegation. While applauding its arrival at the plant, he said independent journalists were kept from covering the visit, allowing the Russians to present a one-sided, “futile tour.” And he said that while Grossi agreed to support Ukrainian demands for the demilitarization of the plant — including the withdrawal of Russian forces from it — the IAEA has yet to issue such a call publicly. Fighting in early March caused a brief fire at its training complex, and in recent days, the plant was briefly knocked offline because of damage, heightening fears of a radiation leak or a reactor meltdown. Officials have begun distributing anti-radiation iodine tablets to nearby residents. Experts have also expressed concern that the Ukrainian staff is overworked and stressed out from the occupation of the plant by Russian forces — conditions they say could lead to dangerous errors. Grossi said after his initial tour that the Ukrainian employees are "in a difficult situation, but they have an incredible degree of professionalism. And I see them calm and moving on.” Russian Foreign Minister Sergey Lavrov said Moscow expects “impartiality” from the team. “We are taking all the necessary measures to ensure that the plant is secure, that it functions safely and that the mission accomplishes all of its plans there,” he said. Ahead of the visit, Russia's Defense Ministry reported that Ukrainian forces unleashed an artillery barrage on the area and sent a group of up to 60 scouts to try to seize the plant on the Dnieper River. It said that the Ukrainian troops arrived in seven speedboats but that Russian forces “took steps to destroy the enemy,” using warplanes. Some of the Ukrainian shells landed 400 meters (yards) from the plant’s No. 1 reactor, Russian authorities said. The Russian-installed administration in Enerhodar reported that at least three residents were killed early Thursday by Ukrainian shelling. Ukrainian officials, meanwhile, accused Russian forces of shelling Enerhodar and a corridor that the IAEA team was set to go through. Neither side’s version of events could immediately be independently verified. The fighting came as Ukraine endeavored to start the new school year in the middle of a war. Just over half of the country's schools are reopening to in-person classes despite the risks. In other developments, authorities with the Russian-backed separatist government in the eastern region of Donetsk said 13 emergency responders were killed by Ukrainian shelling in Rubtsi, a village in neighboring Kharkiv province. Much of the fighting in recent weeks and months has centered on the area.