Kyrgyzstan's south has been volatile since an outbreak of ethnic violence on June 10 killed up to 2,000 people, set off a wave of refugees and destroyed entire Uzbek neighborhoods.
Russia and the United States both operate military bases in the former Soviet Central Asian republic and are concerned about the threat of regional instability.
Ole Solvang, a researcher with Human Rights Watch, told Reuters from a hospital in Osh that clashes broke out again on Monday when government forces went on patrol in the Uzbek neighborhood of Nariman on the outskirts of Osh.
"The military have been going around doing checks... and looking for weapons. A lot of people have been beaten up," he said by telephone. "It's very tense. The authorities have to be very careful about ways of doing these checks." Timur Kamchibekov, a spokesman for the Kyrgyz interim government, told Reuters from Osh that Kyrgyz forces had come under attack in the Uzbek neighborhood.
"During a security operation, law enforcement forces were met with armed resistance in the village of Nariman. According to preliminary information, two civilians died," he said.
Solvang said about 20 people were wounded, adding that doctors were unable, for security reasons, to reach outlying areas where they suspect more wounded people might be in need of help.
Tolekan Ismailova, a prominent human rights campaigner, said by telephone from Osh four people had been killed in an operation conducted by local police on Monday, based on her research and interviews with witnesses.
She said the operation was carried out in response to the killing of a Kyrgyz policeman in an Uzbek settlement last week.
"There are a lot of wounded hiding in the houses. Young people are being taken away somewhere," she said. "It's unacceptable to act like this toward civilians." The official death toll from last week's violence is 208 but the interim government, which came to power after a revolt in April toppled President Kurmanbek Bakiyev, says it could be up to 2,000.
The new government has accused Bakiyev loyalists of instigating the violence in the ethnically divided and flammable south ahead of a referendum on Sunday on reform of the constitution. Bakiyev, in exile in Belarus, has rejected the allegations.
