Russia and Ukraine traded claims of rocket and artillery strikes at or near Europe’s largest nuclear plant on Sunday, heightening fears that the fighting could trigger a massive leak of radioactivity. Russian forces took control of the Zaporizhzhia nuclear power plant immediately after the start of the war and hold adjacent lands along the left bank of the great Dnieper River. Ukraine controls the right bank, including the towns of Nikopol and Marhanets, each about 10 kilometers (six miles) from the facility. Russian Defense Ministry spokesman Igor Konashenkov said on Sunday that Ukrainian forces attacked the plant twice in the past day and that shells fell near buildings that store reactor fuel and radioactive waste. “One projectile fell in the area of ​​the sixth power unit and the other five in front of the sixth unit’s pumping station, which provides cooling for this reactor,” Konashenkov said, adding that radiation levels were normal. In another apparent attack on Sunday, Russian forces shot down an armed Ukrainian drone targeting one of the Zaporizhzhia plant’s spent fuel storage areas, a local official said. Vladimir Rogov, a regional official based in Russia, said on the Telegram messaging app that the drone crashed into the roof of a building without causing significant damage or injuries. Nearby, heavy gunfire overnight left parts of Nikopoli without electricity, said Valentin Reznichenko, governor of the Dnipropetrovsk region. Rockets damaged a dozen homes in Marchanets, according to Yeven Yevtushenko, head of the district administration that includes the city of about 45,000 people. The city of Zaporizhzhia, about 40 kilometers up the Dnieper River from the nuclear plant, also came under Russian fire, damaging dozens of apartment buildings and houses and injuring two people, city council member Anatoly Kurtev said. Russian forces hit a Ukrainian air force helicopter repair shop in Zaporizhia, Konashenkov said. Neither side’s claims could be independently verified. Across the river from the nuclear plant, Ukrainian missiles hit the Kakhovka hydroelectric plant and the nearby town three times on Sunday, said Vladimir Leontyev, head of the local administration based in Russia. The factory dam is an important road along the river and a potentially key supply route for Russia. The dam forms a reservoir that supplies water for the Zaporizhzhia nuclear power plant. In eastern Ukraine, where Russian and separatist forces are trying to take control, shelling hit the large and strategically important cities of Kramatorsk and Sloviansk, with no casualties reported, said Pavlo Kyrylenko, the governor of the Donetsk region. Konashenkov said Russian missiles killed 250 Ukrainian soldiers and reservists in and near Sloviansk. Ukrainian officials did not comment on the claim, in keeping with their policy of not discussing the damage. Sloviansk resident Kostandin Daineko told The Associated Press that he was falling asleep when an explosion ripped through his apartment windows. “I opened my eyes and saw how the window frame was flying over me, the frame and pieces of broken glass,” he said. Russian and separatist forces hold much of the Donetsk region, one of two that Russia has recognized as sovereign states. Authorities last week began distributing iodine tablets to residents living near the Zaporizhzhia plant in case of radiation exposure. Much of the concern centers on the cooling systems for the plant’s nuclear reactors. The systems require electricity, and the plant was temporarily shut down Thursday because of what officials said was fire damage to a transmission line. A failure of the cooling system could cause a nuclear meltdown. Intermittent shelling has destroyed the power plant’s infrastructure, Ukraine’s nuclear power company Energoatom said on Saturday. “There are risks of hydrogen leakage and release of radioactive substances and the risk of fire is high,” it said. The U.N. atomic energy agency tried to strike a deal with Ukrainian and Russian authorities to send a team to inspect and secure the plant, but it remained unclear when the visit might take place. —— Andrew Katell contributed to this report from New York.