Viktor Yanukovych, whose fraud-tainted victory in the 2004 Ukrainian presidential elections sparked the Orange Revolution, was expected Thursday to become the country's next prime minister after the president submitted his former rival's candidacy to parliament.

President Viktor Yushchenko acknowledged that his decision to nominate the man he once denounced could cause misunderstanding and dismay, but called it a historic chance to mend the country's deep divisions.

"I ask people to understand that we have a unique chance (to do what) we talked about on Independence Square, (to do what) we dreamed every day — to unite both sides of the Dniper (River) in understanding," Yushchenko said in an early morning address. Kiev's Independence Square was the center of the Orange Revolution mass protests and the Dniper River bisects Ukraine.

Yushchenko's decision followed four months of wrangling after parliamentary elections gave no party a majority of seats. The country fell into political paralysis as parties argued, maneuvered and shifted alliances to form a majority coalition.

CountryWatch: Ukraine

In the end, Yanukovych's Party of Regions — which won the biggest chunk of seats in the March parliament elections — formed a coalition with the Socialists, who had defected from an earlier coalition that included Yushchenko's bloc, and the Communists.

The new coalition nominated Yanukovych to be premier — the post he had held when he ran against Yushchenko. Yushchenko announced he would accept the nomination only at around 2 a.m. Thursday — two hours after the constitutional deadline for him to make a decision expired.

Lawmakers were expected to vote on Yanukovych's nomination in the afternoon, after he and Yushchenko signed a national unity agreement.

Yushchenko said the agreement preserves his pro-Western and reformist policies. With that agreement, Yushchenko's party is ready to join the coalition, said lawmaker Roman Zvarych.

But some members of the president's coalition said they would refuse to join Yanukovych.

If Yushchenko's party joins the coalition, it would increase the pressure on Yanukovych to continue Ukraine's Westward drive. But Yanukovych has repeatedly maintained that a priority should be put on relations with Russia.

"There is a risk that it could just become a document of intentions that leads nowhere," said Kiev-based political analyst Serhiy Taran.

The decision to name Yanukovych premier marks a stunning comeback for the man who left politics in disgrace after Ukraine's Supreme Court threw out his fraud-marred presidential win in 2004 and Yushchenko won the court-ordered revote.

Yanukovych bounced back in the March election, adopting Western-style campaign tactics as he spent countless months in get-out-the-vote rallies in eastern and southern Ukraine. He has emphasized a softer position, saying he supports cooperation with NATO, joining the World Trade Organization and membership in the European Union. However, he has refused to back down from his support for Russian language speakers and his insistence that membership in NATO could only be decided by a public referendum.