Moscow (AFP) - Russia on Saturday accused Kiev and Western nations of distorting a Ukraine peace agreement hours before it was to take effect and as fighting raged in the east of the country.

"Ukraine's official representatives...as well as those of several Western countries, the United States in particular, have essentially expressed solidarity with the opinion of radical nationalists in the Verkhovna Rada (parliament) and have begun to distort the contents of the Minsk agreements," the foreign ministry said in a statement.

The accord was reached Thursday after marathon negotiations by the Russian, French and Ukrainian presidents and the German chancellor.

Kiev and the West are "putting in doubt the implementation of the document's concrete measures" officially backed by Russia's Vladimir Putin, France's Francois Hollande, Ukraine's Petro Poroshenko and Germany's Angela Merkel, the statement said.

While the representatives from the eastern Ukrainian separatist regions of Donetsk and Lugansk "are showing their responsible attitude towards their commitments, the statements made by Ukrainian politicians in Kiev raise doubts," Moscow said.

"We reaffirm that the principal message of the Minsk accords is that it is necessary to end the fighting, to withdraw heavy weapons and to start a real constitutional reform in Ukraine," the statement said.

Russia wants "all the signatories of Thursday's Minsk accord" -- Kiev, the pro-Russian rebels, and the Organization for Security and Cooperation in Europe -- "as well as the parties that supported the process, including Germany and France, to do everything possible to assure that this accord is strictly respected."

Fighting continued to rage in eastern Ukraine on Saturday, just hours before the midnight deadline.