BISHKEK, Kyrgyzstan — The United Nations urged Kyrgyzstan on Tuesday to take quick, decisive action to end indiscriminate ethnic killing in its volatile south as the interim government braced for new attacks in the north.
At least 176 people have been killed around the southern cities of Osh and Jalal-Abad in violence that began Thursday and escalated into the deadliest clashes the impoverished Central Asian state has seen in 20 years.
As the violence escalated over the weekend, witnesses said gangs armed with automatic rifles, iron bars and machetes set fire to houses and shot fleeing residents.
Osh appeared considerably calmer Tuesday, but the atmosphere remained tense. A senior U.S. official said in Vienna that the violence appeared to have stopped spreading and might be receding.
The events have fueled concern in Russia and the United States, both of whom operate military air bases in Kyrgyzstan.
UN officials have said the number of ethnic Uzbeks fleeing the clashes for neighboring Uzbekistan may soon exceed 100,000 and warned against a spreading of the violence outside Kyrgyzstan's borders.
"It seems indiscriminate killings, including of children, and rapes have been taking place on the basis of ethnicity," said Navi Pillay, United Nations high commissioner for human rights.
She urged Kyrgyz authorities to take "swift and decisive action" to protect people irrespective of their ethnic origin.
Interim leader Roza Otunbayeva, who took power after a deadly revolt in April that ousted President Kurmanbek Bakiyev, said the real death toll from the violence could be "several times" higher than the official numbers, Interfax reported.
The interim government has said more violence could occur in the capital, Bishkek, and another region of the north.
"We are keeping enough forces in Bishkek and are working to ensure that Bishkek stays under our control," said Otunbayeva, who has accused supporters of Bakiyev, who is now in exile in Belarus, of stoking ethnic conflict.
Bakiyev has denied that he is behind the violence. His son Maxim was arrested in Britain after he landed at an airport in southern England, Kyrgyz media reported.
Pillay's office said Tuesday that the violence appeared to have begun with five coordinated attacks by men carrying guns and wearing balaclavas.
"We have strong indications that this event was not a spontaneous interethnic clash — that it was to some degree orchestrated, targeted and well-planned," her spokesman Rupert Colville told a briefing in Geneva.
Analysts say that if southern Kyrgyzstan, which shares the densely populated Ferghana Valley with Uzbekistan and Tajikistan, descends into chaos, it could help militant Islamists gain a firmer footing in the volatile region.
UN special envoy Miroslav Jenca said Kyrgyzstan should take every step possible to ensure that violence did not spread to other parts of Central Asia.
"The most important task now is to stop the bloodshed," Jenca told reporters. "This conflict should be localized."
Interim leader Otunbayeva said Uzbekistan had shut the border to block "those seeking revenge."
"Otherwise it would have already been a war between the two states," she said.
The Organization for Security and Cooperation in Europe said it had seen signs of ethnic cleansing in clashes between Kyrgyz and Uzbeks in southern Kyrgyzstan.
And independent UN rights investigators said they had concerns about reports of a shoot-to-kill policy adopted by the provisional government, which has sent some troops to the south.
But Nancy McEldowney, U.S. principal deputy assistant secretary for European and Eurasian affairs, said the violence appeared to be easing.
"I know that there was a concern initially about the violence spreading, and we saw the violence spread from Osh to Jalal-Abad," she said.
"But reports over the course of the last 24 hours have been that spreading had abated," she said on the sidelines of an OSCE meeting in Vienna.
The region's main security bloc, the Russian-led Collective Security Treaty Organization, on Monday proposed sending helicopters and equipment to help stop the violence.
But Kyrgyzstan said it had been told not to expect an immediate dispatch of troops.
The CSTO is seen as the most likely vehicle for a deployment of peacekeepers from Russia, which is vying for influence with China and the United States in the region.
"Moscow greatly fears instability in this region," Eurasia Group analysts said in a note. "The violence poses the prospect of a lawless area in the south of Kyrgyzstan that could, in the Kremlin's view, eventually provide safe harbor to Islamic militants and ease the operating environment for organized crime and narco-trafficking groups."
Washington uses its air base at Manas in the north of Kyrgyzstan, about 300 kilometers from Osh, to supply forces fighting the Taliban in Afghanistan.
The United Nations and the European Union have urged the interim government to stick to plans for a referendum on June 27 and parliamentary elections in October. Otunbayeva said Tuesday that there were no plans to delay the referendum.
The violence is the worst in Kyrgyzstan since 1990, when Soviet leader Mikhail Gorbachev sent troops to Osh after hundreds were killed in a dispute that started over land ownership.
The interim government said it had helped evacuate foreign citizens, including 200 Chinese and 198 Indians and citizens of Turkey, Pakistan, European Union nations, Afghanistan and Turkmenistan.
Pakistan and Germany sent aid to the troubled southern regions, and China was expected to send food and medical supplies Tuesday.