One Ukrainian serviceman was killed and another wounded in fighting with rebels in the east, military spokesman Vladislav Seleznyov said on Thursday, as Kiev accused rebels of increasing violations of a cease-fire deal.

President Petro Poroshenko, whose initiative to boost the armed forces by a third was passed easily in parliament, has called the cease-fire the last chance for peace with the rebels.

Accusations of continued violence on both sides show the fragility of the peace accord, agreed in Minsk last month, which calls for the withdrawal of heavy weapons from the frontline.

Some 6,000 people have been killed in fighting since separatists took up arms last year in Ukraine's eastern industrial heartland - the "Donbass" - in response to the overthrow of president Viktor Yanukovich in Kiev.

Interior ministry adviser Zoryan Shkiryak said the rebels were not only ­failing to stop firing and pull back, but in fact building up forces in southern Donetsk province, near the Ukrainian-held port city of Mariupol.