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, according to the (BBC).
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.
Some 6,000 people have been killed since fighting broke out in eastern Ukraine between pro-Russian separatists and the Ukrainian government a year ago.
The Ukrainian government, Western leaders and NATO say there is clear evidence that Russia has helped the rebels with heavy weapons and soldiers. Independent experts echo that accusation.