( Reuters ) - Rescue teams battled a tenacious fire in a Ukrainian colliery on Monday as they strove to locate 30 miners missing underground after a methane blast that killed at least 70 miners.
Distraught relatives milled about near the entrance of the pit in Donetsk, heart of Ukraine's Donbass coalfield, seeking news of missing miners in what is likely to become the country's deadliest accident since independence from Soviet rule in 1991.
One of 28 miners in hospital remained in serious condition.
"The situation has become worse," Andriy Klyuyev, head of a commission of inquiry, told reporters.
"The temperature has risen. But rescue work is proceeding. There are always chances for a rescue ... If we put the fire out, we will finish matters today."
But trade union officials have said since Sunday's explosion 1,250 metres ( 3,800 feet) underground at the Zasyadko mine that there is little chance of finding survivors among the missing.
Post-Soviet Ukraine's worst mining accident was in March 2000, when 80 miners were killed in an explosion at a coal mine near the eastern town of Luhansk.
"My son Vyacheslav is missing in section number four," said Roza Kononova, one of several dozen tearful relatives gathered in a nearby park hoping for encouraging news of the rescue.
Miners at the pit, one of Ukraine's most profitable in a sector plagued by outdated equipment, earn monthly wages equivalent to about $1,000 -- more than three times the national average salary.
Many were clearly distraught at the accident which sent fire and smoke roaring through underground shafts.
"After an accident like this, lots of miners quit and I'm thinking about it too," said a miner identifying himself as Nikolai. "Why should I do this? I live alone with my daughter. What happens if I end up getting killed?".
President Viktor Yushchenko was to visit Donetsk on Monday to press efforts to investigate the explosion.
On Sunday, he said the government of his longstanding rival, Prime Minister Viktor Yanukovich, had failed to reorganise the mining sector and improve its safety record.
Yanukovich visited the mine in his native region on Sunday and promised prompt compensation to miners' families.
Other industrial sectors in Ukraine have also been plagued by accidents causing loss of life or damage -- including the derailment of a train carrying phosphorus in July and a gas explosion killing 20 people in an apartment block last month.
Authorities have declared Tuesday a national day of mourning throughout the ex-Soviet state of 47 million. Three days of mourning were announced in the region and funerals were scheduled for Tuesday.