Fighting continued overnight between government troops and pro-Russian rebels in east Ukraine, despite renewed diplomatic efforts to enforce a truce.
Ukraine said six government soldiers were killed in the past 24 hours and army positions were fired on 26 times near the rebel stronghold of Donetsk.
The rebels said one of their fighters was killed during attacks by the army.
On Monday, Ukraine, Russia, Germany and France called for the withdrawal of more weapons from the frontline.
The four nations also expressed “grave concern” over the surge in fighting.
The statement came after talks in Berlin between the foreign ministers of Ukraine, Russia, Germany and France.
In a separate development on Tuesday, a Russian military journalist was seriously injured by a booby trap in the village of Shyrokyne, near the strategic port of Mariupol in the south.
‘Differences of opinion’
In Berlin, the four foreign ministers called for the withdrawal of mortars and heavy weapons with a calibre of less than 100mm as well as all types of tanks.
But Germany warned that the talks had also emphasised differences over the year-old conflict in Ukraine’s Donetsk and Luhansk regions.
“It was again a very long, very intensive discussion which in parts was very controversial,” German Foreign Minister Frank-Walter Steinmeier said.
“During these talks today the differences of opinion between Kiev and Moscow also became clear once again.”
But, he added, all parties had also reaffirmed the commitment to a ceasefire agreed in February in the Belarusian capital, Minsk.
Both sides are largely thought to have adhered to the deal – until a recent escalation of fighting in the flashpoints near Donetsk and Shyrokyne.
Ukraine and the rebels claim to have withdrawn heavy weapons from the line of contact – although this has not been confirmed by monitors from the Organisation for Security and Co-operation in Europe (OSCE).
Ukraine, Western leaders and Nato say there is clear evidence that Russia has helped the rebels with troops and heavy weapons. Russia denies that, insisting that any Russians on the rebel side are “volunteers”.
More than 6,000 people have been killed in clashes since the rebels seized large parts of the Donetsk and Luhansk regions last April – a month after Russia annexed Ukraine’s southern Crimea peninsula.