An explosion at a Ukrainian coal mine killed at least 17 miners on Friday, the Emergencies Ministry said, the latest in a series of accidents that has raised concern over safety standards in the industry.

Two miners were injured in the explosion at the Sukhodilska-Eastern mine in the Luhansk region in the former Soviet republic's coal mining heartland, and nine were missing.

The blast early on Friday at the mine in the town of Sukhodilsk was the deadliest of its kind since 2007, when a methane explosion at a nearby mine killed more than 100 people.

"The cause of the blast is being determined," the ministry said in a statement. Interfax news agency quoted a regional mining official as saying the explosion was caused by a concentration of methane gas inside the mine, where 252 people were working at the time.

Ukraine's energy and mining sectors have been plagued by accidents, against a background of poor infrastructure and lax safety regulations.

Mariya Mikheyeva stood outside the company office in Sukhodilsk on Friday, waiting for news of her son-in-law, who was in the mine at the time of the blast and is missing.

"My husband worked at a mine, developed many illnesses and died before the age of 60," she told Reuters TV. "(Now) my son-in-law is missing... His son is also in training for the same job," she said, wiping back tears.

Rinat Akhmetov, the owner of the mine and Ukraine's richest man, offered his condolences. "Unfortunately, working conditions in Ukrainian mines are extremely hard," he said in a statement.

President Viktor Yanukovich and Prime Minister Mykola Azarov visited the site of the accident later in the day, their offices said. Yanukovich ordered the government to set up a commission to investigate the blast.

Interfax quoted him as saying the accident could have been caused either by electrical equipment malfunctioning or by the drilling-and-blasting work carried out a day earlier.

"First of all, this must not happen again," Yanukovich's office quoted him as saying.

FEW JOBS BESIDES MINING

In a separate accident also on Friday, a piece of heavy machinery collapsed at a state-owned coal mine near the town of Makiyivka in the neighbouring Donetsk region, killing four people and injuring four, the Emergencies Ministry said. Seven people were missing after the accident, it added.

Ukraine produced more than 75 million tonnes of energy and coking coal last year. Employment opportunities outside the mining sector are limited in towns built next to major mines.

The blast-hit mine is owned by Krasnodon Coal, Ukraine's second largest mining company which is part of Metinvest, run by Akhmetov, who sponsored Yanukovich's 2010 presidential campaign.

Akhmetov's SCM owns 71.25 percent of Metinvest.

The mine, which has been in operation since 1980, accounts for a quarter of Krasnodon Coal's output. In 2009, Krasnodon Coal produced 5.4 million tonnes of coking coal.

The company said it would pay 1 million hryvnias (76,064 pounds) to the family of every miner who died in the accident.

In 1992, 58 people were killed in a methane explosion at the same mine. A fire broke out at the mine last month but no one was hurt