Fighting has escalated in eastern Ukraine ahead of an international summit aimed at ending the conflict.
At least two dozen people have been killed over the past 24 hours.
The leaders of Russia, Ukraine, Germany and France will meet in Belarus to discuss plans for peace - which includes greater autonomy for the pro-Russian East.
More than 5,000 people have been killed since last April - and the West has warned Russia's Vladimir Putin to accept peace or face further sanctions.
Channel 4's chief news correspondent Alex Thomson spoke to Newstalk Breakfast this morning, and started by explaining what is expected to happen at today's talks:
The planned meeting, in the Belarussian capital Minsk, follows last week's discussions between Russian president Vladimir Putin and Ukrainian leader Petro Poroshenko, led by Germany and France.
Details of last week's talks have not been revealed although a French diplomatic official said they included the setting up of a demilitarised zone between Ukraine and Russia, which remained a sticking point.
US President Barack Obama has come under increasing pressure to provide military aid to Ukraine amid claims Russia has been arming the rebels - claims denied by Moscow.
Moscow has also hit out at calls for the West to arm Ukraine in the fight against the separatists.
After meeting German Chancellor Angela Merkel in Washington on Monday, Mr Obama said he had ordered his team to see "whether there are additional things we can do to help Ukraine bolster its defences in the face of Russian aggression".
However, Ms Merkel is firmly opposed to arming the Ukrainian military, saying it will hinder attempts to find a solution to the violence. "It has always proved to be right to try again and again to sort such a conflict," she said through a translator.
On Monday, Kiev said about 1,500 Russian troops had crossed the border into Ukraine via rebel-controlled border posts over the weekend.
Russia has repeatedly denied supplying the rebels with troops or heavy weapons, but Western military experts say all the evidence suggests otherwise.
