A gas buildup and explosion in a Siberian coal mine on Thursday killed at least 52 people — including six rescuers — in the country’s worst mining disaster in over a decade, Russian officials said.

The accident occurred early in the morning at the Listvyazhnaya mine in the Kemerovo region of Russia, about 2,200 miles east of Moscow, after a ventilation shaft began filling with gas, Russia’s Investigative Committee reported.

Rescue efforts at the mine, which plunges 1,300 feet into the earth, continued throughout the day even as the death toll kept rising. Miners initially considered missing were gradually shifted to the list of the dead until late Thursday, when the authorities said they had been forced to suspend rescue operations because of a high concentration of methane in the mine.

Interfax, the Russian news agency, reported that there appeared to be no hope of finding anyone else alive.

At least some of the dead were workers who suffocated. Others may have been trapped.

The country’s deputy prosecutor general told Interfax that a methane explosion had most likely made it impossible for the miners to get out.

One miner, Mikhail Pozdnyakov, told Channel One, Russia’s national television network, that he had heard “a loud bang” and that he “couldn’t see anything afterward.”

“Everything got filled with dust and ashes, and whoever could just fell on the ground,” Mr. Pozdnyakov said from a hospital. “Seven people got out with me and five got left there.”

Coal mine accidents have been common in Russia since Soviet times, with some attributed to the sporadic enforcement of regulations.

This year alone, several government agencies have checked the Listvyazhnaya mine dozens of times. They discovered hundreds of violations, issued fines and even ordered work suspended, Russia’s technology watchdog said in a statement.

But the mine was open for business Thursday, and by the end of the day, dozens were dead.

The Investigative Committee said it had opened a criminal investigation into the disaster and had already arrested the mine’s director, his deputy and the head of the mine’s sector where the incident occurred.

The Kemerovo region accounts for more than half of coal produced in Russia. It has also been the site of some of the worst mining accidents.

In 2007, an explosion at the Ulyanovskaya mine killed more than 100 people. In 2010, more than 90 were killed in two explosions at the Raskadskaya mine. In 2004, 13 miners died at the same mine where the explosion occurred Thursday.