A mob vents its fury against a member of Ukraine's parliament after a vote granted an amnesty to pro-Russia rebels. Courtesy Sky News.

KIEV is accusing Moscow of massing its troops in annexed Crimea on the Ukraine border, rattling nerves just as Ukraine President Petro Poroshenko prepares to meet US counterpart Barack Obama.

The apparent push north by about 4000 troops in the Black Sea peninsula came despite Russia’s declared backing of a peace overture by Kiev to try to end five months of conflict in the rebellious east.

“According to our information, almost all military units of the Russian Federation stationed in the north of occupied Crimea ... were pushed to the administrative border with Ukraine along with all their equipment and ammunition,” Ukraine National Security and Defence Council spokesman Andriy Lysenko told reporters.

Mr Poroshenko holds his first White House talks with Mr Obama overnight, seeking to gain security guarantees from Washington as he steers the former Soviet state on a clear westwards path.

The meeting comes just two days after parliament in Kiev ratified a historic pact with the EU and adopted legislation offering self-rule to the east in votes crucial to the future shape of the nation.

Mr Poroshenko’s offer won Russia’s support, although the pro-Moscow rebels have been more dismissive, saying it will not stop their fight for full independence.

The self-rule law and accompanying legislation granting amnesty to fighters were drawn up under a truce signed 13 days ago that has eased — but not halted — deadly violence around insurgent strongholds in eastern Ukraine.

The situation around the flashpoint city of Donetsk appeared to be calm on Thursday after days of shelling that has left around 30 civilians and soldiers dead.

Moscow, echoing comments by Washington and Brussels, said Kiev’s overture was a “step in the right direction” towards ending a conflict that has cost almost 2900 lives and sent East-West tensions spiralling to post-Cold War highs.

The law was approved just moments before MPs also ratified a landmark political and economic pact with the EU that decisively pulls Ukraine away from Moscow’s sphere of influence.

Mr Poroshenko will cast Russia as a global menace when he meets Mr Obama, in the hope of winning a “special status” guaranteeing his troubled nation’s security and support for future membership of NATO.

While Mr Obama does not want to be drawn into a military standoff with a nuclear-armed rival, Washington has joined the EU in imposing waves of punishing sanctions on Russia.

A report by the European Bank for Reconstruction and Development (EBRD) showed how sanctions were biting, forecasting Russia’s economy will shrink 0.2 per cent next year.

Russian President Vladimir Putin said overnight that the measures violated the principles of the World Trade Organisation.

But the crisis is even more severe for Ukraine, with the EBRD projecting a massive nine per cent contraction this year. The country is already relying on a huge IMF aid package to stay afloat.

Analysts say Ukraine’s peace overture to the east is a high-stakes gamble that could definitively splinter the country by creating a Russian-speaking zone that would depend more on Moscow than Kiev.