The ex-Soviet republic of Ukraine is in the grip of a new political crisis on Thursday, sharpened by deep divisions over whether to support or oppose Russia in its confrontation with Georgia.

The crisis flared just ahead of a visit by US Vice President Dick Cheney, who was due later in the capital Kiev in a demonstration of support for Ukraine's increasingly fragile pro-Western leadership and goal of joining NATO.

President Viktor Yushchenko on Wednesday accused opponents in parliament of a coup attempt and threatened early elections after the prime minister's party sided with pro-Russian deputies to pass laws cutting his powers.

Prime Minister Yulia Tymoshenko, a former ally of Yushchenko, in turn accused the president of having "destroyed" the governing coalition by pulling out of an alliance with her party after the approval of the legislation.

On Thursday, the independent daily Gazeta 24, quoting unnamed lawmakers in Tymoshenko's parliamentary bloc, said the prime minister and the leader of the pro-Moscow Regions Party had already agreed to a new coalition.

The report said Tymoshenko would remain as prime minister while the Regions Party leader, former prime minister Viktor Yanukovych, would take over as parliament speaker.

"Tymoshenko will dance to Moscow's tune," the Ukrainian newspaper Kommersant quoted a member of the president's Our Ukraine party as warning.

Commenting on the disarray, one Ukrainian official, speaking anonymously, told AFP: "We've messed up again. This is not good at all ahead of the Evian summit" -- a September 9 meeting in France between the European Union and Ukraine intended to advance Kiev's EU membership goals.

Ukrainian analysts said Cheney would try to bolster Ukraine's pro-Western push during his visit.

"Cheney will try to push Ukraine towards preserving the pro-Western coalition," which has not yet been formally disbanded, said Valery Chaly, an analyst at the Razumkov Centre for political and economic research.

He said the crisis would however "strengthen the argument" of sceptics opposed to Ukraine joining the European Union and NATO. Ukrainian and EU officials appeared to agree the crisis would hurt Ukraine's image.

On Thursday, a pro-Russian member of parliament put forward a motion calling for Foreign Minister Vladimir Ogryzkov to be sacked for allowing a US warship to visit the Sevastopol naval base, which is located on Ukrainian territory and uneasily inhabited by Russia's and Ukraine's navies.

The minister should be sacked for "the illegal entry of the American warship Dallas into the bay of Sevastopol," Interfax quoted the deputy, Vasiliy Kiselyov, as saying.

Tymoshenko and Yushchenko were the icons of the 2004 pro-Western Orange Revolution and have each been considered Western-leaning politicians despite persistent and sharp disagreements on domestic political issues.

Last month however Yushchenko's backers accused Tymoshenko of "high treason" for allegedly siding with Moscow in its conflict with Georgia.

They have suggested she is now doing the Kremlin's bidding, a charge she has firmly denied.

Tymoshenko abstained from a vote last month aimed at imposing restrictions on the movements of Russia's Black Sea fleet, which is based in Sevastopol and was involved in military action against Georgia.

The Crimea Peninsula where the fleet is based has a large Russian-speaking population and some officials and analysts have speculated that the region could be the next flashpoint in tensions between Russia and the West.

An EU diplomat speaking in Brussels on Wednesday said: "This crisis is very worrying.... This is going to make the EU-Ukraine summit more difficult."

Segodnya, a newspaper close to the pro-Russian opposition, said the crisis was "very annoying news" for Washington, which wants "Tymoshenko and Yushchenko working together to bring Ukraine into NATO."