Fighting in eastern Ukraine has intensified ahead of much-anticipated peace talks, with both sides claiming significant advances and the government accusing rebels of shelling a town far behind the front line.
The fighting, which the UN says has killed more than 5,300 people since April, comes ahead of a crucial summit involving Western leaders tomorrow, as well as peace talks later today.
Ukrainian President Petro Poroshenko told parliament that Russian-backed rebels launched an artillery strike on the town of Kramatorsk, which is more than 30 miles away from the front line.
Mr Poroshenko said the first round of rocket fire hit the headquarters of the Ukrainian command in eastern Ukraine and the second landed in a residential area.
The government-controlled Donetsk regional administration said three people were killed and 15 injured in the artillery strike.
Kramatorsk was the site of major fighting until July when pro-Russian separatists retreated.
Local website Donetskiye Novosti posted photos from the scene, showing an artillery shell stuck in the ground next to a residential building and two bodies lying nearby.
The volunteer Azov battalion, loyal to Kiev, said on social media that it had captured several villages north east of the strategic port of Mariupol, pushing the rebels closer to the border with Russia. However, rebel military spokesman Eduard Basurin said in a televised news conference the rebels had not retreated.
The Azov said rebels shelled the village of Kominternove, east of Mariupol, causing unspecified civilian casualties.
The rebels also reported advances. Mr Basurin said they had surrounded the railway hub of Debaltseve, the focus of fierce fighting in past weeks, cutting it off from a major road.
A video posted online by a rebel-sympathisng website showed separatists moving along the route while the bloodied bodies of Ukrainian soldiers lay on the side of the road.
At least seven Ukrainian troops were killed overnight in the east, military spokesman Anatoliy Matyukhin said. In the rebel stronghold of Donetsk, which comes under constant shelling, two civilians were killed and 12 injured.
The fierce fighting and a mounting death toll comes amid renewed efforts to work out a peaceful solution in a conflict that has displaced at least a million people and left the powerhouse of the Ukrainian economy in ruins.
Representatives of Ukraine, Russia, rebels and the Organisation for Security and Cooperation in Europe are meeting for long-anticipated talks later today in Minsk to lay the groundwork for a meeting tomorrow between the leaders of Russia, Ukraine, Germany and France.
The Kremlin today warned the West ahead of the talks against sending weapons to Ukraine or putting pressure on Russia.
President Vladimir Putin's spokesman, Dmitry Peskov, told the Russian News Service radio station that any talk about imposing new sanctions on Russia or arming the Ukraine government would destabilise the situation.
In Washington yesterday, President Barack Obama and German Chancellor Angela Merkel rallied behind efforts to reach a long-shot diplomatic resolution to the conflict, but they offered no clear path for how the West would proceed if talks this week fail.
Ms Merkel staunchly opposed arming Ukraine's beleaguered military while Mr Obama dangled the prospect that the US could for the first time send weapons to Ukraine.