More than 30 people have been killed in an explosion at a coal mine in the separatist stronghold of Donetsk in eastern Ukraine, Reuters reported, citing a local official.
"Rescue workers have not yet come to the place of the explosion, they are removing the poisonous gas and then will go down," Vladimir Tsymbalenko, head of the local mining safety service, said.
The Russian foreign minister has called on Ukraine to distance itself from 'extremists' and pursue a course towards peace.
Sergey Lavrov says 'tangible progress' has been achieved in implementing the package of measures agreed in Minks and the ceasefire is being consolidated.
A Ukrainian military spokesman said Ukrainian photographer Serhiy Nikolayev has been killed by shelling in east Ukraine despite a ceasefire deal.
"We don't know all the details, but there was shelling in Pesky today," spokesman Andriy Lysenko told Reuters news agency, saying the unnamed journalist had been taken to a military hospital where he died from his wounds.
Pesky is a government-held town on the front line, north-west of rebel-controlled Donetsk.
Britain will not deploy combat troops to Ukraine, which is fighting pro-Russian separatists along its eastern flank, Michael Fallon told parliament.
"We are not deploying combat troops to Ukraine and will not do so," Fallon said when asked whether the deployment of military personnel would provoke so-called mission creep.
Britain is preparing to send 75 troops and military staff to help with training and is considering more Ukrainian requests for help, the Defence Secretary added.
Mr Fallon confirmed British personnel will be based around Kiev or in western Ukraine, away from the fighting in eastern Ukraine.
British military personnel will be deployed to Ukraine in the coming weeks to provide advice and training to government forces in the country, the Prime Minister has revealed.
The announcement came as David Cameron gave evidence to the Commons Liaison Committee on the UK's assistance in the ongoing situation between Ukraine and Russia.
He said the UK had still not reached the stage of providing lethal support, an array of non-lethal assistance had been sent.
Over the course of the next month we are going to be deploying British service personnel to provide advice and a range of training, from tactical intelligence to logistics to medical care, which is something else they have asked for.
We will also be developing an infantry training programme with Ukraine to improve the durability of their forces. This will involve a number of British service personnel, they will be away from the area of conflict but I think this is the sort of thing we should be helping with.
Economic sanctions against Russia should be extended and toughened if Russian President Vladimir Putin does not pull back from Ukraine, the Prime Minister has said.
Speaking at a liaison committee meeting, David Cameron said if "miraculously" Russia withdrew its weapons and upheld ceasefires, the sanctions would be lightened - but in the meantime, he said the UK, US and Europe had to take a stand against his actions.
Mr Cameron said the sanctions were necessary to protect Moldova and the Baltics from being destabilised next.
He also criticised "serious" violations of British airspace by Russian craft, but said the UK was "more than capable" of defending itself.
I'm sure the Russian's would like us to react in a more volumous way about it.
So far this year the RAF has scrambled the quick reaction aircraft twice, last year it was eight times, if you go back to 2011 it was 10 times, and in 2007 it was 19 occasions.
I think we should be strong, measured and clear, but we should be absolutely confident in our air force, in our Typhoons and the pilots that we have. We are more than capable of protecting our airspace.
Russia's President has said that war with neighbouring Ukraine was unlikely.
"I think that such an apocalyptic scenario is unlikely and I hope this will never happen," he told Russia State television.
Vladimir Putin was asked if he expected a war between Russia and Ukraine. A transcript of the interview was published on the Kremlin website. Putin also said he did not see the need for another meeting with France, Germany and Ukraine on resolution of the conflict in eastern Ukraine.
Ukraine's military said two of its soldiers had been killed and 10 wounded in the past 24 hours, signalling that fighting has not stopped to allow a truce deal to be implemented.
Spokesman Valentyn Fedychev said Ukrainian forces had been shelled 27 times in the past day.
Fighting has diminished in eastern Ukraine since rebels defied a ceasefire to capture the town of Debaltseve last Wednesday, but Kiev says it is still not quiet enough to allow it to withdraw artillery from the front.
The Ukrainian people are furious that the recent ceasefire has collapsed and their homes and lives are continuing to be destroyed.
Following today's explosion in Kharkiv, where two people were killed, the locals of Danetsk have predicted revenge and a 'blood bath' if the fighting does not stop.
ITV News Correspondent Martin Geissler reports.
Ukraine has said that it feared unrest could spread beyond eastern areas held by pro-Russian separatists, after an explosion killed two people at a memorial rally in Kharkiv on Sunday.
Four people, who had been trained in Russia, have been arrested following the blast, which killed a policeman and a demonstrator at the rally in the biggest city in the east, 200 km from the war zone.
A week after a ceasefire agreement that Moscow-backed rebels ignored to capture a strategic town, Kiev and its Western allies are trying to determine whether the separatists will now halt, or advance deeper into territory the Kremlin calls "New Russia".