Kiev says fresh clashes between its soldiers and pro-Russia fighters have left three Ukrainian soldiers dead and two wounded in Ukraine's east.
"Over the past 24 hours three Ukrainian soldiers were killed in combat," Ukrainian military spokesman Oleksandr Motuzyanyk said on Sunday.
"It happened as a result of an enemy mortar attack near Krasnogorivka," he said, warning about a "sharp increase" in tensions in the conflict zone.
Russian-speaking people in eastern Ukraine have witnessed deadly clashes between pro-Russia forces and Ukrainian army ever since Kiev launched military operations in April 2014 to crush protesters calling for greater autonomy in the region.
The United States and its allies in Europe accuse Moscow of having a hand in the conflict in eastern Ukraine, a claim Moscow denies.
International mediators, namely Russia, France, Germany and Belarus, have tried to persuade the two sides of the conflict to remain committed to a peace agreement between the conflicting sides. However, the peace process is stagnant and deadly clashes between Ukraine's troops and pro-Moscow forces are a frequent occurrence.
The autonomy-seeking regions of Donetsk and Lugansk blame Kiev for stalling the peace process.
The conflict has left nearly 10,000 people dead and over 21,000 others injured, according to the United Nations.
A peacekeeping observatory force from the Organization for Security and Cooperation in Europe (OSCE) has been deployed to the conflict zone to monitor the front line and record any ceasefire violations.