Batken, Kyrgyzstan: Rioting spread across the south of this strategically important Central Asian nation on Sunday as the authorities failed to contain mobs that appeared to be increasingly engaging in targeted ethnic violence.
The official death toll from four days of clashes neared 100 people, though the unrest seemed so widespread that the figure is likely to go far higher. Reports from the region said bands of ethnic Kyrgyz were seeking out Uzbeks, setting fire to their homes and killing them.
Thousands of Uzbeks have fled to the nearby border with Uzbekistan, and the authorities were said to have lost control of Osh, Kyrgyzstan's second largest city.
On Saturday, the fragile Kyrgyz provisional government asked neighboring Russia to send in peacekeeping troops, but Russia, which has a small military base in the north and has been a political patron of this former Soviet republic, said only that it would consider the request.
"The situation in the Osh region has spun out of control," Kyrgyzstan's acting president, Roza Otunbayeva, said Saturday. "Attempts to establish a dialogue have failed, and fighting and rampages are continuing. We need outside forces to quell confrontation."
A spokeswoman for President Dmitri A. Medvedev of Russia said that no decision on providing military aid would be made until at least Monday, when Russia will consult with other members of the Collective Security Treaty Organization, a regional security alliance of former Soviet republics.
"A decision about deploying peacekeeping forces to Kyrgyzstan can only be made collectively with all members of the C.S.T.O.," the spokeswoman, Natalya Timakova, said Saturday evening. She also said that Russia was continuing to ship humanitarian assistance, including medicine, to Kyrgyzstan.
It remained unclear what started the violence, which threatens to undermine the already fragile provisional government that took power in April after rioting deposed the country's president. The interim government has never fully established control in parts of the south, where supporters of the ousted president, Kurmanbek S. Bakiyev, have frequently clashed with those loyal to the new government.
The country is host to an important United States military base on the outskirts of the capital, Bishkek, that is used to support the NATO mission in Afghanistan.
On Saturday, heavily armed gangs battled on the streets of Osh, burning and looting as they rampaged through the city.
"It was raining ash the whole afternoon, big pieces of black and white ash," said Andrea Berg, a Human Rights Watch employee holed up her apartment in the city. "The city is just burning. It's totally out of control."
The rioters at one point commandeered two armored personnel carriers from troops stationed in the city, said Timur Sharshenaliyev, a spokesman for the government there. Soldiers were able to take only one back.
The provisional government passed a decree giving the police and soldiers permission to open fire on rioters to prevent attacks on civilians and government buildings, according to a statement on the government's Web site.
The authorities also ordered a partial mobilization of military forces throughout the country, suggesting the government feared the spread of violence to other regions. Soldiers with automatic weapons gathered at the Bishkek airport early Sunday morning awaiting transport to Osh, some downing a few vodka shots before they set off.
Yelena K. Bayalinova, a spokeswoman for the Kyrgyz Health Ministry, said Saturday that in addition to the killings, nearly 1,000 people had been wounded, most with gunshot wounds.
The recent politically inspired clashes in the region have reopened a historic ethnic fault line, with gangs of heavily armed Kyrgyz youths clashing with members of the region's sizeable Uzbek minority. Much of Mr. Bakiyev's base in the region, his ancestral home, is Kyrgyz, while many Uzbeks support the new government.
Mr. Sharshenaliyev, the government spokesman in Osh, said on Saturday that the military had opened a corridor to allow Uzbek women, children and the elderly to escape across the border, though he said he did not know whether Uzbekistan was prepared to receive them. The Associated Press reported that several children were killed in a stampede at one border crossing.
Uzbekistan said it was "extremely alarmed and concerned" about the situation. The Uzbek Foreign Ministry said in a statement that violence against Uzbeks was being carried out in a manner calculated to provoke ethnic conflict.
The Kremlin said that Mr. Medvedev spoke Saturday with the presidents of Kazakhstan and Uzbekistan about the violence. Russia also sent a plane to Kyrgyzstan to provide humanitarian aid and medical assistance, as well as to evacuate the wounded.
Russia and the United States have in recent years been jockeying for influence in Kyrgyzstan, and deploying soldiers there could help solidify Russia's foothold. Russia has frequently chafed at the American military presence in what it considers its sphere of influence.
Russia appeared to support the protest movement that led to Mr. Bakiyev's ouster, and it has sought closer relations with Kyrgyzstan's new authorities.
Officials of the provisional government frequently travel to Moscow for talks with high-ranking Russians, including Mr. Medvedev and Prime Minister Vladimir V. Putin.
Under Mr. Bakiyev, the Kyrgyz government appeared to favor the United States. Mr. Bakiyev incensed the Kremlin when he reneged on a tacit agreement to close the American base in exchange for more Russian aid.
The provisional government took control after riots forced Mr. Bakiyev from power on April 7. In those riots more than 80 people were killed when the police and presidential guards opened fire on demonstrators, who had gathered in Bishkek to protest government corruption and rising utility prices.
The new government, though unelected and made up of an uneasy alliance of political forces, quickly established control over the capital and the north of the country, but not in the south.
The south of Kyrgyzstan is part of the Ferghana Valley, a fertile strip of land that has a long history of interethnic strife and includes parts of Uzbekistan and Tajikistan. Similar violence between Kyrgyz and Uzbeks in Osh in 1990 left hundreds dead and only abated when the Soviet government sent in troops.
Clifford J. Levy contributed reporting from Moscow