AVDIIVKA, UKRAINE — Fighting between government troops and Russia-backed separatist rebels in eastern Ukraine escalated on Tuesday, killing at least eight people overnight, injuring dozens and briefly trapping more than 200 coalminers underground, the warring sides reported.



Rebels in Donetsk said an electricity sub-station was damaged in shelling, cutting power to the Zasyadko coal mine in Donetsk. The mine is notorious for its safety standards; 33 people were killed there in 2015 by a methane blast.



With elevators not working, the miners had been trapped underground for several hours before local authorities found the backup generators outside the mine to get the elevators working. By midday on Tuesday, at least 152 of 200 men had been able to get out.



Separatist military spokesman Eduard Basurin, in an interview with Russian state Rossiya 24 television on Tuesday, denied reports that separatist shelling cut power lines and heating stations in Avdiivka, saying they had been damaged earlier.



The artillery shelling, which appears to be the worst in many months, was concentrated around the government-controlled town of Avdiivka, home to a giant coking plant. Its director said on Monday that preparations were being made to stop production, something rarely done throughout the conflict that has claimed more than 9,600 lives since it began in 2014. A cease-fire deal struck in Minsk in 2015 has helped to reduce but not stop the fighting.



Oleksandr Turchynov, chairman of the Ukrainian Security and Defense Council, said Tuesday that heavy shelling around Avdiivka, on the northern outskirts of the separatist stronghold of Donetsk, killed at least three troops and injured 24 more. The press office of the Ukrainian government's operation in the east reported an unspecified number of civilian casualties. It also said the rebels turned down the government's offer to cease fire to allow the removal of the dead and wounded.



In Donetsk, the rebels' Donetsk News Agency reported four rebel fighters died and seven were injured overnight as well as three civilians. One civilian was killed in shelling in Donetsk, Basurin told Russian news agencies.



Dmitry Peskov, spokesman for Russian President Vladimir Putin, on Tuesday accused the Ukrainian government of provoking the crisis. The Kremlin has "reliable information" that Ukrainian volunteer battalions crossed the front line Monday night and tried to capture rebel territory, Peskov told reporters in Moscow.



Salvos of heavy-caliber artillery were heard throughout the night and late morning in Avdiivka, where several thousand people have been without electricity for days. Fighting has cut water supplies for most of the town and it was left without heating in the dead of winter. Temperatures plunged to 0 Fahrenheit on Tuesday morning.



The local hospital was flooded overnight with injured soldiers, who were operated on and taken to a town further away from the front line, according to an Associated Press reporter at the scene. Several private houses were damaged in the shelling.



Kiev-based independent political analyst Vadim Karasyov said an escalation in the east could be beneficial to both the separatists and the Ukrainian government.



"Kiev is eager to win support of the new Trump administration, and for this they need to show that separatists and the Kremlin are derailing the peace accords," he said. "For the Kremlin, it's important to show that it holds war and peace in its hands — if the new U.S. administration wants peace in Ukraine, it needs to offer something in return."



Local water supply company Water of Donbass said on Monday the Donetsk Water Filtration Station, a crucial source of clean water for both sides of the conflict, came under shelling. About 10 projectiles landed in a reservoir that feeds the filtration plant, the company said. It was not immediately clear whether this affected supplies to customers.



Both sides in the conflict committed to cease fire and pull back heavy weaponry under a 2015 truce which they have violated several times.



Pavlo Zhebrivsky, head of the administration in charge of the government-controlled parts of the Donetsk region, said on Facebook his office was working on a plan to evacuate 12,000 residents from Avdiivka.



Donetsk News Agency cited the rebel military command accusing government troops of attacking their positions Tuesday morning in the south of the conflict zone, to the east of Mariupol.



Ukrainian President Petro Poroshenko had cut short his visit to Germany on Monday because of the fighting.



Associated Press