KIEV, May 24 ??“ Special police forces stormed in the building of the General Prosecutor??™s Office on Thursday trying to block President Viktor Yushchenko??™s move to replace the top prosecutor Sviatoslav Piskun.

The forces, Berkut, were sent by Internal Affairs Minister Vasyl Tsushko after Yushchenko had issued the decree replacing Piskun with Viktor Shemchuk, a loyalist, on the post.

The Berkut troops, which are controlled by the pro-Russian government coalition, confronted and outnumbered security agents guarding the office, helping Piskun to get through.

The clash highlights a major escalation of political crisis in Ukraine suggesting that talks between pro-Russian coalition and pro-Western opposition parties aimed at ending the crisis had finally collapsed.

The use of special forces comes despite earlier assurances from senior members of the pro-Russian government coalition that the parties will try to settle the crisis through talks.

Yushchenko reacted strongly to the development. He called Tsushko??™s order to storm the prosecutor??™s office ???a criminal act.???

Defense Minister Anatoliy Hrytsenko, who controls the ultimate military force in Ukraine, backed the president and suggested that the army may step in to prevent further clashes. Hrytsenko accused Tsushko of criminal responsibility for sending the troops and thus breaking the law.

???As the minister, as a politician, Tsushko cut short his career,??? Hrystenko said. ???I am confident that he will face a criminal investigation in the near future, today or tomorrow, and he will be responsible.???

Yushchenko was holding an emergency meeting with top security and defense officials, including Hrytsenko and Army??™s chief of staff Serhiy Kyrychenko, late Thursday apparently mulling how to respond to the use of force by the pro-Russian coalition.

The development may force the president, the Commander-in-Chief by constitution, to declare an emergency in the country that would allow him to assume control over the government.

???For the first time in independent Ukraine there has been a clash between different forces,??? Hrytsenko said in an interview with Channel 5. ???This is a dangerous development that must be stopped.???

Meanwhile, Tsushko issued a special statement on Thursday explaining the use of the troops by what he had said was illegal order from the president to sack Piskun.

???We call on the international community to support us and to convince the president of Ukraine to respect the constitutional order and the rule of law in the country,??? Tsushko said.

???The escalation of the situation, an attempt to use forces, the standoff between the authorities may cause the civil war in Ukraine,??? Tsushko said. (tl/ez)