Outside the presidential office, police were blocking protesters and establishing a new security belt. The roads in the city center were closed and vehicles were forbidden. More police troops were rushing toward the presidential office, witnesses said.

Bakiyev has ordered a state of emergency in Bishkek and three other cities, local television reported.

Amid waves of opposition protests in the Kyrgyz capital and elsewhere, Bakiyev also ordered a curfew between local time 10:00 p.m. (1600 GMT) Wednesday and 6:00 a.m. Thursday (0000 GMT) in Bishkek.

The Kyrgyz parliament is scheduled to sit on Thursday. Sources told Xinhua that the parliament might convene an emergency session Wednesday night on the president's order.

Opposition supporters marched toward the presidential office in the city center from different directions in the morning. Some protesters seized quite a few police vehicles and drove them toward the presidential office.

The protesters were attempting to storm into the building, and were demanding negotiations with President Bakiyev and Prime Minister Daniyar Usenov. They threatened to occupy the presidential office if their demands were not met.

In a related development, the regional government buildings in Naryn and Chui states were overrun by protesters earlier Wednesday, witnesses told Xinhua.

About 3,000 protestors gathered at a central square in the provincial capital of Naryn.

The U.S. embassy in Bishkek Wednesday urged the Kyrgyz government and protesters to start negotiations as early as possible.

The U.S. embassy said in a statement that the U.S. government was deeply concerned about the latest unrest in some Kyrgyz cities.

The statement hoped that all the parties concerned in Kyrgyzstan would abide by law, begin talks as soon as possible, and solve their rifts within the framework of law.

Earlier, Russia urged restraint between Kyrgyz authorities and the opposition and called on them to resolve their disputes through democratic means instead of violence.

U.N. Secretary-General Ban Ki-moon on Wednesday said he was "shocked" over the deadly clash in Kyrgyzstan and appealed for concerned parties to "show restraint."

"The secretary-general is shocked by the reported deaths and injuries that have occurred today in Kyrgyzstan," said a statement issued by Ban's spokesman.

"He once again calls on all concerned to show restraint," the statement said, "He urgently appeals for dialogue and calm to avoid further bloodshed."

The unrest on Wednesday came one day after Tuesday's violence in the northern Kyrgyz town of Talas, during which at least 15 police officers were missing, 16 civilians and 85 policemen were injured, Prime Minister Usenov said.

The unrest broke out after the head and deputy head of the main opposition Ata-Meken party were arrested Tuesday. Kyrgyz authorities said the unrest had been put under control.

Usenov told an urgent parliamentary meeting that the country's situation is still under the control of his government and that the government will never negotiate with "rioters."

Meanwhile, more than 10 opposition leaders have been set free by the government after a large number of protestors gathered outside the building where they were held.

The government released opposition leader Isa Omurkulov, a member of the Social Democratic party, along with Temir Sariyev and several others, the Reuters news agency reported.