Berlin (AFP) - Germany on Monday criticised as "unacceptable" Russia's decision to recognise passports issued by separatist rebels in Ukraine's eastern regions of Lugansk and Donetsk.

"The recognition of travel documents of the self-declared, so-called people's republics of Lugansk and Donetsk undermines the unity of Ukraine," said Chancellor Angela Merkel's top spokesman Steffen Seibert.

"It directly contradicts everything that was agreed in Minsk (peace talks) and is therefore unacceptable."

Authorities in pro-Russian rebel-held areas about a year ago began issuing passports very similar to Russian ones bearing a two-headed eagle on a red backdrop.

Russia announced Saturday a decree recognising such passports and other documents, a move Kiev called a "provocation".

The decree, signed by Russian President Vladimir Putin, was described by Moscow as "temporary" until a "political solution" is found to bring peace to the region.

Both Ukraine and the West -- which has imposed sanctions on Russia as a result of the unrest -- say the separatist regions receive humanitarian and military backing from Moscow, although Russia has not until now officially recognised them.

The Russian decree said that "Ukrainian citizens and stateless persons who live there" will henceforth be able "to enter Russia and exit Russia without a visa".

The document added that the measures were "temporary, until the situation in the Donetsk and Lugansk regions finds a political solution based on the Minsk accords" signed in February 2015 and designed to bring a truce to the region.

The war has cost cost some 10,000 lives since Ukraine's mostly Russian-speaking eastern industrial regions revolted against Kiev's pro-Western government, after the ouster of the former Soviet republic's Kremlin-backed president.

A German foreign ministry spokesman on Monday voiced hope that Moscow and Kiev remain committed to ending the conflict.

"We believe that the two sides, Moscow and Kiev, who signed the Minsk agreement on February 12, 2015 are still fundamentally interested in implementing this agreement, and to thus restore the full sovereignty of Ukraine," he told a press conference.

"We are directing this appeal to the Russian Federation... and we will, of course, continue our dialogue with... Moscow and Kiev."