The aircraft that was carrying the pro-Western Ukrainian head of state had to abandon its journey from Kiev to the western city of Lviv because of 'technical problems,' the president's office told AFP.

'The president's plane made an emergency landing at Borispol airport due to technical problems 20 minutes after take-off,' spokesman Irina Vannikova said, adding, 'Nobody was injured.'

Upon returning to the airport near Kiev, his delegation then took the plane that was waiting for Ms Tymoshenko, who was due to travel to Moscow for talks with Russian Prime Minister Vladimir Putin.

'The president changed planes' to continue the visit to Lviv, said Ms Vannikova, adding that the trip would be shortened.

Almost simultaneously, the office of Prime Minister Tymoshenko, who has been at loggerheads with Mr Yushchenko, said her scheduled flight to Moscow was delayed amid reports the president took her plane instead.

'The government delegation was deprived of its plane in a bid to thwart the negotiations' with Putin, a Ms Tymoshenko spokesman, said cited by Interfax news agency.

Both Interfax and Kanal 5 television said Mr Yushchenko had used the aircraft originally scheduled to transport Ms Tymoshenko after its emergency landing.

A presidential spokesman said Mr Yushchenko had no information about the matter, while the prime minister's office was could not be reached for comment.

Ms Tymoshenko later left for Moscow aboard a small private plane, Interfax cited a source as saying, adding the prime minister's delegation had to wait at the airport until a flight could be organised.

Mr Yushchenko and Ms Tymoshenko have had a love-hate relationship since 2004, when they joined forces in the so-called Orange Revolution to overturn the rigged election of pro-Russian candidate Mr Viktor Yanukovych as president.

Mr Yushchenko's party, which had formed a government with the Tymoshenko bloc, abandoned the coalition in Sept after a series of spats resulting from the bloc's decision to back the pro-Russian opposition on a vote to reduce the president's powers.

Unless a new alliance is formed by mid-Oct, the president has the right to dissolve parliament and call new elections, which Mr Tymoshenko opposes, according to political analysts.

Mr Tymoshenko said on Wednesday that she would accept any conditions to salvage a pro-Western coalition amid fears the pro-Russian opposition would seize control.

'We will close our eyes and accept any ultimatums in order to preserve Ukraine's strategic orientation, to preserve the parliament and not to throw the country into a new crisis,' she said with apparent spite. -- AFP