Fighting erupted between ethnic Kyrgyz and Uzbek groups early Friday and grew larger during the day.
Rioters smashed windows, looted businesses and burned cars, prompting the Kyrgyz government to declare a state of emergency in Osh and three neighboring districts. A Kyrgyz government spokesman says authorities sent armored vehicles to the site of the riots and imposed a nighttime curfew.
Southern Kyrgyzstan was the power base of former president Kurmanbek Bakiyev, who was overthrown in an April uprising in which 85 people were killed.
A researcher for Human Rights Watch in Osh told VOA the city was calm late Friday morning, after she heard gunshots through the night.
Andrea Berg says international organizations in Osh closed Friday and told staff to remain at home.
Russian President Dmitri Medvedev and Chinese President Hu Jintao called for a quick resolution to the situation in Kyrgyzstan. The leaders spoke at a summit of regional leaders in the Uzbek capital Tashkent Saturday.