A methane explosion at a coal mine in central Kazakhstan killed at least five people and injured another four on Thursday, officials said.
"A sudden release of gas during the drilling of a drainage well led to the deaths of five workers" in the Lenin mine belonging to ArcelorMittal, Ruslan Imankulov, a spokesman for the country's emergency ministry, told AFP.
Imankulov added that "four people were hospitalised and 106 were evacuated".
The mine is located in the resource-rich region of Karaganda, whose governor said the accident had been caused by an "explosion of methane" -- a gas that, when combined with a certain amount of oxygen, can combust.
An investigation into potential violations of safety rules has been opened by a government commission.
In a statement, Kazakh President Kassym-Jomart Tokayev offered his "condolences to the families and friends of the deceased workers", and wished a "speedy recovery to the injured".
Kazakhstan, a former Soviet republic and Central Asia's leading economy, has significant deposits of oil, gas and coal, as well as uranium, manganese, iron and chromium.
Mine accidents are frequent in the countries of the former Soviet Union due to the dilapidation of facilities and a lax approach to safety.