Russian troops control about 80% of the fiercely contested eastern Ukrainian city of Sieverodonetsk and have destroyed all three bridges leading out of it but Ukrainian authorities are still trying to evacuate the wounded, a regional official said Tuesday. Serhiy Haidai, governor of the eastern Luhansk region, acknowledged that a mass evacuation of civilians from Sieverodonetsk now is “simply not possible” due to the relentless shelling and fighting in the city. Ukrainian forces have been pushed to the industrial outskirts of the city because of “the scorched earth method and heavy artillery the Russians are using,” he said. “There is still an opportunity for the evacuation of the wounded, communication with the Ukrainian military and local residents,” he told The Associated Press by telephone, adding that Russian forces have not yet blocked off the strategic city. About 12,000 people remain in Sievierodonetsk compared to its pre-war population of 100,000. More than 500 civilians are sheltering in the Azot chemical plant, which is being relentlessly pounded by the Russians, according to Haidai. Also Read: Moscow-backed officials try to solidify rule in Ukraine In all, 70 civilians were evacuated from the Luhansk region in the last day, the governor said. A Russian general, meanwhile, says a humanitarian corridor will be opened Wednesday to evacuate civilians from the besieged Azot chemical plant in Sievierodonetsk. Col-Gen. Mikhail Mizintsev said evacuees would be taken to the town of Svatovo, 60 kilometers (35 miles) to the north in territory under the control of Russian and separatist forces. He said the plan was made after Ukraine called for establishing an evacuation corridor leading to Ukrainian-controlled territory. Mizintsev, head of the National Defense Management Center, is accused by Ukraine of human rights violations while commanding troops during the long siege of Mariupol, Ukraine’s key port on the Sea of Azov that has been taken over by the Russians. Russian forces in the last few weeks have pressed hard to capture Ukraine’s eastern industrial Donbas area, which borders Russia and is made up of the regions of Luhansk and Donetsk.  “The situation is difficult,” Ukrainian President Volodymyr Zelenskyy said in a news conference Tuesday with Danish media. “Our task is to fight back.” Jan Egeland, the Secretary-General of the Norwegian Refugee Council, one of the aid organizations supplying food to the people in the Donbas, said fighting in the past few weeks has made regular food distributions impossible. Now, he said, the remaining civilians in the city “are almost entirely cut off from aid supplies after the destruction of the last bridge.”

A senior U.S. official warned that Russia plans to annex large portions of eastern Ukraine later this month, and the Mariupol steel mill that has become the city’s last stronghold of resistance came under renewed assault a day after the first evacuation of civilians from the plant. Michael Carpenter, U.S. ambassador to the Organization for Security and Cooperation in Europe, said Monday that the U.S. believes the Kremlin also plans to recognize the southern city of Kherson as an independent republic. Neither move would be recognized by the United States or its allies, he said. Carpenter cited information that Russia is planning to hold sham referendums in the so-called Donetsk and Luhansk people’s republics that would “try to add a veneer of democratic or electoral legitimacy” and attach the entities to Russia. He also said there were signs that Russia would engineer an independence vote in Kherson. He noted that mayors and local legislators there have been abducted, that internet and cellphone service has been severed and that a Russian school curriculum is soon to be imposed. Ukraine’s government has said Russia also has introduced the ruble as currency there. In bombed-out Mariupol, more than 100 people — including elderly women and mothers with small children — left the rubble-strewn Azovstal steelworks on Sunday and set out in buses and ambulances for the Ukrainian-controlled city of Zaporizhzhia, about 140 miles (230 kilometers) to the northwest, according to authorities and video released by the two sides. Mariupol Deputy Mayor Sergei Orlov told the BBC that the evacuees were making slow progress. Authorities gave no explanation for the delay. At least some of the civilians were apparently taken to a village controlled by Russia-backed separatists. The Russian military said some chose to stay in separatist areas, while dozens left for Ukrainian-held territory. Also Read: Civilians rescued from Mariupol steel plant head for safety In the past, Ukraine has accused Moscow’s troops of taking civilians against their will to Russia or Russian-controlled areas. The Kremlin has denied it. The Russian bombardment of the sprawling plant by air, tank and ship picked up again after the partial evacuation, Ukraine’s Azov Battalion, which is helping to defend the mill, said on the Telegram messaging app. Orlov said high-level negotiations were underway among Ukraine, Russia and international organizations on evacuating more people. The steel-plant evacuation, if successful, would represent rare progress in easing the human cost of the almost 10-week war, which has caused particular suffering in Mariupol. Previous attempts to open safe corridors out of the southern port city and other places have broken down, with Ukrainian officials accusing Russian forces of shooting and shelling along agreed-on evacuation routes. Before the weekend evacuation, overseen by the United Nations and the Red Cross, about 1,000 civilians were believed to be in the plant along with an estimated 2,000 Ukrainian defenders. Russia has demanded that the fighters surrender; they have refused. As many as 100,000 people overall may still be in Mariupol, which had a prewar population of more than 400,000. Russian forces have pounded much of the city into rubble, trapping civilians with little food, water, heat or medicine. Some Mariupol residents got out of the city on their own, often in damaged private cars. As sunset approached, Mariupol resident Yaroslav Dmytryshyn rattled up to a reception center in Zaporizhzhia in a car with a back seat full of youngsters and two signs taped to the back window: “Children” and “Little ones.” “I can’t believe we survived,” he said, looking worn but in good spirits after two days on the road. “There is no Mariupol whatsoever,″ he said. “Someone needs to rebuild it, and it will take millions of tons of gold.” He said they lived just across the railroad tracks from the steel plant. “Ruined,” he said. “The factory is gone completely.” Anastasiia Dembytska, who took advantage of the cease-fire to leave with her daughter, nephew and dog, said she could see the steelworks from her window, when she dared to look out. “We could see the rockets flying” and clouds of smoke over the plant, she said. Ukrainian President Volodymyr Zelenskyy told Greek state television that remaining civilians in the steel plant were afraid to board buses because they feared they would be taken to Russia. He said he had been assured by the U.N. that they would be allowed to go to areas his government controls. More than 1 million people, including nearly 200,000 children, have been taken from Ukraine to Russia since the Russian invasion began, Russia’s Defense Ministry said Monday, according to TASS. Defense Ministry official Mikhail Mizintsev said that number included 11,550 people, including 1,847 children, in the previous 24 hours, “without the participation of the Ukrainian authorities.” He said those civilians “were evacuated to the territory of the Russian Federation from the dangerous regions of the Donetsk and Luhansk People’s Republics,” and other parts of Ukraine, according to the report. No details were provided. Also Read: Evacuation of civilians from Ukrainian steel plant begins Also Monday, Zelenskyy said that at least 220 Ukrainian children have been killed by the Russian army since the war began, and 1,570 educational institutions have been destroyed or damaged. Thwarted in his bid to seize Kyiv, the capital, Russian President Vladimir Putin has shifted his focus to the Donbas, Ukraine’s eastern industrial heartland, where Moscow-backed separatists have been battling Ukrainian forces since 2014. Russia said it struck dozens of military targets in the region, including concentrations of troops and weapons and an ammunition depot near Chervone in the Zaporizhzhia region, west of the Donbas. Ukrainian and Western officials say Moscow’s troops are raining fire indiscriminately, taking a heavy toll on civilians while making only slow progress. The governor of the Odesa region along the Black Sea Coast, Maksym Marchenko, said on Telegram that a Russian missile strike Monday on an Odesa infrastructure target caused deaths and injuries. He gave no details. Zelenskyy said the attack destroyed a dormitory and killed a 14-year-old boy. Ukraine said Russia also struck a strategic road and rail bridge west of Odesa. The bridge was heavily damaged in previous Russian strikes, and its destruction would cut a supply route for weapons and other cargo from neighboring Romania. The attack on Odessa came eight years to the day after deadly clashes between Ukrainian government supporters and protesters calling for autonomy in the country’s east. The government supporters in 2014 firebombed a trade union building containing pro-autonomy demonstrators, killing over 40 people. Ukraine claimed to have destroyed two small Russian patrol boats in the Black Sea. Mariupol, which lies in the Donbas, is key to Russia’s campaign in the east. Its capture would deprive Ukraine of a vital port, allow Russia to establish a land corridor to the Crimean Peninsula, which it seized from Ukraine in 2014, and free up troops for fighting elsewhere.          

Ukrainian forces and Russia-backed rebels in eastern Ukraine began exchanging prisoners Sunday in a move aimed at ending their 5-year-long war.