President Viktor Yushchenko held crisis talks to find a way out of Ukraine's political stalemate, but his appeal for compromise was shattered when lawmaker Yulia Tymoshenko lashed out against what she termed calls for artificial unity.

"In not a single democratic country in the world is it possible to unite all political forces," said Tymoshenko, one of the leaders of the 2004 Orange Revolution, in an angry speech during the round-table discussions. "As a rule, there are those in power and the opposition."

The ex-Soviet republic has been locked in turmoil since Viktor Yanukovych's pro-Russian Party of Regions won the most seats in a March parliamentary election, besting the pro-Western reformers who backed Yushchenko, but falling short of a majority.

Yushchenko's allies teamed up with Tymoshenko's bloc and the Socialist Party to create a majority coalition in June, but the Socialists defected before it had time to form a new government. The Socialists united with the Party of Regions and the Communists in a new coalition that proposed Yanukovych as prime minister.

Fraud allegations during Yanukovych's run for the presidency against Yushchenko in 2004 triggered the massive protests known as the Orange Revolution; the Supreme Court declared the vote invalid, and Yushchenko defeated Yanukovych in a rerun.

Yushchenko so far has not forwarded Yanukovych's nomination as premier to the parliament. But because the parliament convened more than 60 days ago without forming a government, Yushchenko technically has the right to dissolve the legislature and call new elections.

Faced with the equally unattractive prospects of calling new elections or allowing his foe to become prime minister, Yushchenko has been casting desperately for a solution as the Aug. 2 deadline to decide on Yanukovych's candidacy approaches.

"The moment of truth has come, we need to make a decision," Yushchenko said at the start of the round-table, which was televised live.

Yushchenko proposed that all the parties sign a memorandum of national unity that which would safeguard freedom of speech, Ukraine's territorial integrity, liberal economic reforms, European integration efforts and support for a single national language, Ukrainian.

But when the leaders began discussing the memorandum, discussion over whether Ukraine should join NATO sparked heated debate. The Socialists and Communists oppose NATO membership, while Yushchenko countered that cooperation with the alliance was the only way to provide security to Ukraine.

After Yushchenko and Communist Party leader Petro Symonenko exchanged barbs over NATO and the issue of creating a single Ukrainian Orthodox Church, Tymoshenko said the sharp disagreements were an example of why a broad coalition would not work.

"Why should we have two centers of power that rule the country with different courses ... it is only a matter of time before they clash," she said.

But Yanukovych, who is seeking Yushchenko's support, appeared eager to find a compromise. He said that "cooperation with NATO is natural."

However, after six hours of talks, the party leaders failed to reach an agreement on the text of the memorandum. Yushchenko ordered a working group to hash out differences and prepare a final document by Friday morning.

The tension in the room was obvious, even without the main issue — of Yanukovych's premiership — being addressed. When Yanukovych went into a long-winded speech, Yushchenko pointedly interrupted to tell him he had been speaking too long.

Yushchenko ally Roman Bezsmertny said that the president's bloc was willing to work with Party of Regions, but only if a new coalition of national unity was formed. "Today all of us must think first of all about unity," he said.

Ukraine remains deeply divided between the Russian-speaking east, which supports Yanukovych, and the Ukrainian-speaking west, which considers a Yanukovych premiership a betrayal of the Orange Revolution.

Tymoshenko pressed the president to reject any union with Yanukovych, urging him to dissolve parliament and call new elections.

Yushchenko has appeared reluctant to take such a drastic step.

The Party of Regions suggested earlier Thursday that it was ready for some compromises, but would refuse to discuss dropping Yanukovych.