A suspected gas blast at a coal mine in a rebel-held region of east Ukraine has killed at least 30 people and left some 40 missing, officials said.

However, several rebel officials said later that they could not confirm the death toll at the Zasyadko mine in Donetsk.

At least 14 miners were also injured at Zasyadko, which saw Ukraine's worst mine disaster nearly eight years ago.

Relatives of the miners have gathered at the scene to await news.

Donetsk saw heavy fighting between separatist rebels and government troops over the winter but a mine union official, Mikhail Volynets, told a Ukrainian TV channel there had been no fighting in the area in recent days.

While Ukraine's economy has significantly shrunk since the conflict began in April, many coal mines continue to operate in the conflict zone.

Before the conflict, accidents were common in the mines, where safety standards are poor.

Minute's silence

Vladimir Tsymbalenko, head of the local mining safety service, was quoted by Reuters as saying: "According to preliminary information, more than 30 people were killed."

In the Ukrainian parliament in Kiev, speaker Volodymyr Groysman told MPs that 32 people had been killed in a "terrible tragedy". He called for a minute's silence in memory of the victims.

But speaking later to a Russian news agency, Interfax. the head of the rebel rescue service, Alexei Kudenko, said he could not confirm the reports of at least 30 deaths.

A Donetsk district official contacted by Interfax was also unable to confirm the deaths.

At the time of the blast, 230 people were in the shaft.

Of these, 157 had been brought out by 09:00 local time (07:00 GMT), leaving 73 unaccounted for before reports of the deaths, rebel and official sources say.

Despite being one of the region's newer and better-equipped mines, Zasyadko suffered Ukraine's worst mining disaster in November 2007, when 101 people were killed.