Trying to turn back a wave of antigovernment protesters, riot police fired into a crowd and killed several people on Wednesday in the capital of Kyrgyzstan, a former Soviet republic that is the site of an important American air base supporting the mission in nearby Afghanistan, The New York Times reported.
The police used bullets, tear gas and stun grenades against a crowd of thousands massing in front of the presidential office in Bishkek, the capital, news reports said. At least five people were killed and others were wounded.
Tensions have been growing in Kyrgyzstan over what human rights groups contend are the increasingly repressive policies of the president, Kurmanbek Bakiyev.
On Wednesday afternoon, the government declared a national state of emergency as fighting continued in the streets of Bishkek and other provincial centers. Video shot by protesters and uploaded to the Internet showed scenes of protesters clashing with and in some cases pushing back heavily armed riot police.
The United States Embassy in Bishkek issued a statement saying that it was "deeply concerned about reports of civil disturbances."
The Obama administration has sought to cultivate ties with Mr. Bakiyev after he vowed to close the American base on the outskirts of Bishkek last year, then reversed his decision
after the American side agreed to concessions, including higher rent.
Kyrgyzstan, with five million people in the mountains of Central Asia, is one of the poorest countries of the former Soviet Union, and has long been troubled by political conflict and corruption.
The opposition has complained about what is asserts are Mr. Bakiyev's autocratic policies, but it appears that the immediate catalyst for the violence was anger over a sharp increase in prices for utilities.
On Wednesday, the Kyrgyz government accused the opposition of provoking violence. "Their goal is to create instability and confrontation in society," the Kyrgyz parliament said in a statement.
With the unrest deepening, several opposition leaders were arrested, including a former prime minister and presidential candidate, Almazbek Atambaev, and a former speaker of parliament, Omurbek Tekebaev.
The government said it would deal severely with the protesters, but they did not appear to be deterred. The first unrest occurred on Tuesday in the provincial center of Talas, when opposition members stormed government offices.
Russia, which also has military facilities in Kyrgyzstan and a close relationship with the government, appealed for calm.
"We believe that it is important that under the circumstances, all current issues should be resolved in a lawful manner," the Russian Foreign Ministry said.
Mr. Bakiyev easily won another term as president as president
last year over Mr. Atambaev in an election that independent monitors said was tainted by massive fraud.
Mr. Bakiyev first took office in 2005 after the Tulip Revolution the third in what was seen at the time as a series of so-called color revolutions that offered hope of more democratic governments in former Soviet republics.
But since then, he has consolidated power, cracking down on the opposition and the independent media.