Violence has spread in eastern Ukraine, a watchdog warned, as the government in Kiev reported fresh casualties.
While fighting has decreased since a ceasefire between Ukrainian forces and Russian-backed rebels in mid-February, both sides accuse the other of violations.
“The geographical scope of the conflict seems to be spreading,” said Alexander Hug, deputy chief of the Organisation for Security and Co-operation in Europe.
Oleksander Motuzyanyk, a Ukrainian military spokesman, said at least one Ukrainian soldier had been killed and eight injured in clashes with separatists. “Fighting has not died down along a broad stretch of the front line,” Mr Motuzyanyk added, referring to the west and north-east of rebel-held city of Donetsk. “The enemy is actively using heavy weapons. The area of fighting is expanding,” he said.