A methane explosion tore through a coal mine belonging to Mittal Steel in Kazakhstan on Wednesday, killing 41 people in the country's worst mining accident on record.

The Lenin mine, where the blast occurred just before 9 a.m. (11 p.m. EDT), is one of eight supplying coal to the company's Temirtau factory, one of the world's biggest steel plants.

Grigory Prezent, deputy coal department director of Mittal Steel Temirtau, told reporters at the scene it was "almost certain" that 41 people had been killed.

"Thirty-two bodies have been found. They are being recovered at the moment. Another nine are in a dead-end coal face... But it's obvious that they are dead," he said.

The steel plant in the central region of Karaganda, 200 km (125 miles) south of the capital, Astana, continued to work as normal, a company source said, and the accident would not affect customers.

Small groups of tearful relatives, many of them women who brought their children, gathered outside the mine's offices in the town of Shakhtinsk, anxious for news. Others went to the local hospital where three men were in intensive care.

Kazakh President Nursultan Nazarbayev, a former blast furnace operator at the Soviet-era steel plant, offered his condolences to the relatives of the dead miners.

"At this somber moment all citizens of Kazakhstan keenly feel the pain that has befallen the miners of Karaganda," he said on his Web site www.akorda.kz.

Local police said in a statement the blast occurred at a depth of 620 metres and 324 miners working underground were able to scramble to safety. They launched a criminal investigation.

High Temperatures

Mittal's Prezent said that high temperatures from a fire raging in the mine had prevented rescuers from reaching the coal face where the last nine miners were trapped and believed dead.

As well as the three men in intensive care, a further four had been admitted to hospital, he said.

"They have burns to the upper respiratory system, fractured ribs, fractured collarbones and fractured shoulders," he said.

"It's clear this was a methane blast," he said. "Either there was a sudden release of coal and gas that led to the explosion, this will be clear at the coal face. Or, if not, there was an accumulation of gas throughout the shaft."

The Lenin mine, a labyrinth of seven shafts, was commissioned in 1964 and was the scene in November 2002 of a gas explosion in which 13 miners were killed.

Wednesday's accident was the deadliest since Kazakhstan became an independent state in 1991. An explosion at another Mittal coal mine in the Central Asian state in 2004 killed 23.

Mittal shares were trading down 0.11 percent percent at 26.87 euros on the Paris stock exchange at 1502 GMT (11:02 EDT).

The Temirtau steel plant accounts for about four percent of Kazakh gross domestic product and is the nation's single largest corporate employer with a 55,000-strong workforce.

Mittal's Indian-born billionaire owner Lakshmi Mittal paid about $400 million for the steel plant, formerly known as Karmet, in 1995. By 2007 it had planned to have invested around $1.4 billion modernising the site, which ships about 40 percent of its production to China.

Temirtau has an annual design capacity of 6 million tonnes of steel, while the plant's coal mining units can extract up to 12 million tonnes annually.