Ukraine's former PM Yulia Tymoshenko says her erstwhile Orange Revolution ally, President Viktor Yushchenko, plans to team up with his arch-rival.
Ms Tymoshenko says Yushchenko aides are plotting against her
Ms Tymoshenko, who fell out with Mr Yushchenko last year, said her information came from members of the president's Our Ukraine bloc.
The liberal leaders of the 2004 Orange Revolution were beaten in last month's general election by Viktor Yanukovych.
He heads a pro-Moscow party opposed to their pro-Western liberal agenda.
Ms Tymoshenko said Mr Yanukovych's Party of the Regions and Our Ukraine were planning to form an alliance. She condemned it as "a plan to discredit the talks between the democratic forces".
She accused Prime Minister Yuriy Yekhanurov and two other top Ukrainian politicians - Petro Poroshenko and Mykola Martynenko - of undermining her efforts to form a coalition with President Yushchenko's bloc.
Mr Yushchenko and Ms Tymoshenko were allies in 2004
"It has been decided to torpedo, annihilate and ruin the protocol which was signed by the Socialists, Our Ukraine and our bloc," she said.
Mr Yushchenko sacked Ms Tymoshenko as prime minister last September.
Ms Tymoshenko's key demand was to return as prime minister. Her party came second in the 26 March election, ahead of Mr Yushchenko's Our Ukraine.
The two pro-Western liberal leaders had stood together before huge crowds of supporters in Kiev during the 2004 Orange Revolution - the huge street protests which swept them into power.
But their alliance collapsed last year amid bitter rivalry between Ms Tymoshenko and some of Mr Yushchenko's top aides.
Speaking on Ukrainian television on Tuesday, Ms Tymoshenko railed against "Yekhanurov, Poroshenko, Martynenko and all the team who, inside the Our Ukraine bloc, are practically ruining the creation of a
democratic coalition and ruining the future of Ukrainian reform as a whole".
"I believe that the president is capable of defeating those people and of doing his utmost so as not to ruin the future of Ukraine."
Mr Yanukovych was declared the winner of the presidential election in November 2004, but allegations of widespread vote-rigging sent hundreds of thousands of Ukrainians out onto the streets to demand change.
In the Orange Revolution - named after Mr Yushchenko's campaign colour - the election result was overturned and Mr Yushchenko went on to win a re-run.
Mr Yanukovych had been backed by former President Leonid Kuchma, whom the opposition accused of cronyism and corruption.