Fighting continues in eastern Ukraine more than a day after a ceasefire was supposed to take effect.
The Ukrainian military command said the pro-Russian rebels had attacked 112 times since early Sunday, mostly in the bitterly contested Debaltseve area.
A Ukrainian officer said there was also fighting near Mariupol, a port city.
The rebels accused Ukrainian forces of shelling Donetsk airport. Meanwhile, further EU sanctions against Russia have gone into effect.
The new sanctioned list targets 19 officials - most of them in the pro-Russian separatist strongholds of Donetsk and Luhansk, but also two Russian deputy defence ministers and a Russian celebrity singer and MP, Iosif Kobzon.
Armed separatist groups are also targeted, including a Cossack formation. Those listed are now subject to visa bans and asset freezes across the EU.
Russia is accused of fomenting the revolt in eastern Ukraine and giving the separatists reinforcements and heavy weapons. Russia denies doing so, but admits that Russian "volunteers" are fighting there.