KIEV (AFP) - Ukraine's interim president on Tuesday warned of "dangerous signs" of separatism amid fears that pro-Russian eastern regions could agitate for partition as the country tries to resolve its worst post-Soviet crisis.

"In several regions of Ukraine there are very dangerous signs of separatism," Mr Oleksandr Turchynov told parliament.

He said he was consulting with security forces over the issue.

"It is necessary to localise this quickly," Mr Turchynov said, without giving specific details or locations.

Western countries have warned Russia to respect Ukraine's territorial integrity after the weekend ousting of Kremlin-allied president Viktor Yanukovych following the killing of scores of demonstrators in Kiev.

Russian Foreign Minister Sergei Lavrov on Tuesday toned down Moscow's rhetoric, confirming Russia's "position of non-intervention in Ukraine's internal affairs."

The avalanche of change in the deeply divided ex-Soviet state came after months of protests intially sparked by Mr Yanukovych's decision to spurn a historic pact with the EU in favour of closer ties- and a now-stalled US$15 billion bailout (S$19 billion) - from former master Russia.

While the Western-leaning revolution has mobilised the country's Ukrainian-speaking population, at least some in the industrial heartland in the east appeared to be angered by the changes.

Roughly 10,000 people protested on Sunday against the Western-leaning developments in Kiev in Ukraine's second port of Sevastopol in the pro-Moscow Crimean region, home of Russia's Black Sea fleet, calling for Russia to intervene.