MOSCOW – Infighting and allegations of corruption have torn apart the fragile coalition of Western-minded reformers who spearheaded last year’s Orange Revolution in Ukraine, with President Yushchenko yesterday firing the government of charismatic Prime Minister Tymoshenko.

With parliamentary elections only six months away, political analysts say Mr. Yushchenko may be setting himself up for a damaging confrontation with Ms. Tymoshenko that could paralyze attempts to modernize Ukraine’s economy and boost relations with the West.

“The honeymoon is over,” a political analyst with Kiev’s respected Razumkov Center, Yuriy Yakimenko, said. “The people who came together to form this government can no longer get past their divisions and political conflicts.”

In a televised address, Mr. Yushchenko accused his allies of turning against one another in the 10 months since hundreds of thousands of Ukrainians rallied in Kiev’s central square to denounce falsified elections.

“We’ve stepped away from the goals of the revolution,” said Mr. Yushchenko, whose scarred face – the result of alleged dioxin poisoning by his political enemies – became one of the enduring symbols of the revolution. “I could not pretend that nothing was happening. Not for this did I survive poisoning, not for this did people stand on the square. I had to take radical steps.”

Mr. Yushchenko also yesterday accepted the resignation of a close ally, Petro Poroshenko, from his powerful post as the head of the Security Defense Council and suspended another aide – both of whom had been accused by former Orange Revolution allies of corruption. Mr. Yushchenko called the allegations “groundless but very strong,” saying they demanded a response.

He earlier told reporters that conflicts between Mr. Poroshenko and Ms. Tymoshenko “became the everyday agenda” at the Ukrainian Cabinet.

“The president shouldn’t have to be a nanny who has to settle relations between them,” he said. He said he hoped both would remain part of his team, but insisted they learn to work together. There was no immediate word from Ms. Tymoshenko on whether she would seek to retain her position.

Mr. Yushchenko appointed a longtime supporter who now serves as a regional governor, Yuriy Yekhanurov, as acting prime minister. Mr. Yekhanurov said his top priority would be forming a workable government.

Disagreements among Ukraine’s reformers have been simmering for months, but came to a head this week following the resignation of Mr. Yushchenko’s chief of staff, Oleksandr Zinchenko, on Saturday. Mr. Zinchenko accused Mr. Poroshenko and other top officials of “cynically taking advantage of their positions” for personal gain.

Mr. Yushchenko ordered an investigation into the corruption allegations yesterday. Evidence of graft would be especially damaging to Mr. Yushchenko, who came to power on promises to end long-standing corruption in the government of his predecessor, Leonid Kuchma.

The crisis comes amid growing disillusionment with the new government over its failure to tackle economic reforms and increasing consumer prices. A poll conducted last month found for the first time since the Orange Revolution that the percentage of Ukrainians who think the country is headed in the wrong direction exceeds those who think it is in good shape.

Mr. Yakimenko said the dismissal would strengthen the government in the short-term. “This is a positive move that will stabilize the situation in the government and in the country as a whole,” he said. “Hopefully this will allow the government to move on to the important matter of the economy.”

But in the long run, it could set the stage for a showdown between Ms. Tymoshenko’s and Mr. Yushchenko’s allies in March 2006 parliamentary elections. Without the support of Ms. Tymoshenko the president’s hold on parliament is tenuous. If she runs against his forces in March, Mr. Yakimenko said, Mr. Yushchenko could soon be facing an opposition-dominated parliament.