A methane explosion ripped through a coal mine before dawn in war-torn eastern Ukraine, killing at least 10 workers, officials said.
With more than 20 labourers trapped by the rubble, miners were enlisted to assist rescue operations, but work was hampered by limited access to the deep subterranean network.
The explosion at the Zasyadko mine in Donetsk, an eastern city under the control of Russian-backed separatists, was not caused by shelling, rebel authorities said. Eastern Ukraine has been rocked by fighting between government forces and Russian-backed rebels for almost a year, a conflict that has killed more than 6,000 people.
The blast occurred more than 1,000 metres (3,280ft) underground as 230 workers were in the mine, separatist authorities in Donetsk said in a statement, blaming a combustible mixture of methane and air - a common cause of industrial mining accidents.
Contradictory reports trickled out throughout the day as officials loyal to either the central government or rebel authorities independently issued reports. The regional governor's office serving Kiev said that as of the late afternoon, 10 people had been confirmed as having been killed and that the fate of another 23 was unknown.
But rebel officials insisted late into the afternoon that only one person had died.
One lightly wounded miner being evacuated told the Associated Press that he saw five bodies being pulled out, but provided no further details.
It was not possible to immediately reconcile the figures given by different authorities.
One slightly injured miner, 42-year-old Igor Murygin, said at a hospital in Donetsk that he was blown off his feet by the impact of the explosion.
"When I came to, there was dust everywhere. People were groaning," said Mr Murygin, who doctors said had burns over 20% of his body.
Mr Murygin said the mine had installed new equipment and that nothing appeared to be out of order.
The rebels said 15 miners were sent to medical centres in Donetsk.
Miners arriving for their morning shift, shortly after the accident, have helped in the recovery operation. Reaching the stricken portion of the mine has been complicated, however, as one of the three entrances has been forced closed by artillery shelling that has blighted Donetsk. That entrance is the closest to the area where the trapped miners are located.
Ukrainian prime minister Arseniy Yatsenyuk said in Kiev that rebels had prevented a team of 60 Ukrainian rescue workers from reaching the mine to provide assistance.
But leading rebel representative Denis Pushilin denied that Ukrainian authorities had offered any help.
"If we truly need assistance, we will turn to Russia," Mr Pushilin was quoted as saying by the Donetsk News Agency.
Separatist officials trickled into the grounds of the mine throughout the morning, but all refused to respond to questions, a stance that frustrated many miners' families.
Valentina Petrova came to the Zasyadko mine looking for her 47-year-old son, Vladimir.
"He was supposed to retire next year. Everyone is angry that they say on TV that 32 people died but nobody tells us anything," she said.
Workers complained volubly about the long history of safety violations at the Zasyadko mine.
One, who gave only his first name, Kostya, said two of his brothers had been injured in earlier blasts at the same mine.
"We work like crazy for peanuts. We want this place to be safe. We want our children to be able to work here," he told the AP.
The mine has a history of deadly accidents, including one in November 2007 that killed 101 workers, and two more in December 2007 that killed 52 miners and then five more workers.
Ninety-nine people were killed in Ukraine's coal mines in 2014, according to mining safety bodies. Thirteen of those deaths were a direct result of the war in the east, where mines have frequently been struck in artillery duels between rebel and Ukrainian government forces.