Six Ukrainian soldiers have been killed in two separate incidents in the east of the country, government officials say.
Four died after their vehicle was reportedly fired on by pro-Russian separatists in Schastye, close to the separatist stronghold of Lugansk.
Two others were killed when their vehicle hit an anti-tank mine near the government-held port city of Mariupol.
A fragile ceasefire has been in force in eastern Ukraine since February.
There have been isolated violations of the ceasefire, which was agreed by leaders from Ukraine, Russia, Germany and France.