Ukraine on Wednesday was plunged into political turmoil as Prime Minister Yulia Tymoshenko refused to acknowledge defeat in presidential elections and her rival called on her to resign.

The election winner, the pro-Russia Viktor Yanukovych, demanded Tymoshenko stand down as prime minister, warning that Ukraine did not need a new crisis after being plagued by instability in recent years.

But in the clearest indication yet that Tymoshenko will challenge the results, her top ally said the elections had been marred by extensive violations that cast doubt on the overall outcome.

With political tensions riding high, thousands of Yanukovych supporters on Wednesday rallied for the third day in a row outside the headquarters of the election commission with the aim of ensuring the results stand.

"I call on the prime minister to resign and go into opposition," Yanukovych said in a statement posted on the website of his Regions Party.

"I want to remind Mrs Tymoshenko that the basis of democracy is the will of the people. Democratic leaders always accept the results of the elections.

"The country does not need a new crisis," he added.

Tymoshenko has disappeared from public view since making a short comment on Sunday after the release of exit polls and it was unclear when the usually talkative prime minister, famed for her golden hair braid, would reappear. Profile: Yulia Tymoshenko

'Systemic and extensive' 

But Olexander Turchynov, a deputy prime minister and widely seen as Tymoshenko's de-facto number two, emerged to give the highest-level comment from her camp since the results were published.

"In the second round of the Ukrainian presidential elections, falsifications took place which had a substantial impact on the results and put in doubt the outcome of the vote," he said.

Turchynov described the violations as "systemic and extensive" and said the prime minister's supporters were prepared to challenge the results in the courts.

Yanukovych's campaign manager Mykola Azarov then further raised tensions by describing Tymoshenko as "not a representative of the democratic camp... but rather the camp of totalitarian politicians with fascistic tendencies."

With votes from all polling stations now counted, Yanukovych won 48.95 percent of the vote, compared to Tymoshenko's 45.47 percent, the central election commission said, giving him a winning margin of some 3.5 percent.

Though official, these results are still preliminary and must be formally certified by the election commission, a process which may take some weeks.

Tymoshenko was one of the leaders of the 2004 Orange Revolution that sparked hopes of a new start in the ex-Soviet country bordering the EU and Russia but whose ambitions crumbled amid political infighting and economic crisis.

Yanukovych has long been seen as a pro-Kremlin figure and was accused of staging the vote-rigging in the 2004 presidential elections that sparked the Orange uprising.

Relations with Russia

In his first major foreign policy statement since the election, Yanukovych issued a clear signal by saying that relations with Russia would be a priority of his presidency.

"Our countries are closely linked by economics, culture and history," he said.

Ukraine's relations with Russia deteriorated badly under its current president, the vehemently pro-Western Viktor Yushchenko, who rose to power in the Orange Revolution.

On ties with the European Union, Yanukovych said Ukraine could make an indispensable contribution to building a "stable Europe" but made no mention of targeting EU membership, a major aim of the Yushchenko presidency.

Russian President Dmitry Medvedev has already congratulated Yanukovych on his election.

But comment from the United States has been restricted to a brief statement from the US embassy in Kiev, which praised the elections as a consolidation of democracy in Ukraine but made no mention of Yanukovych.

-AFP