Speaking from the capital, Bishkek, the nation's top health official, Dinara Sagynbayeva, said casualty numbers have been rising during the day and are not final.

According to local media reports, clashes between ethnic Kyrgyz and Uzbek youth groups began in Osh, the country's second-largest city, and developed into mass riots.

Rioters set fire to a number of businesses and government buildings, and there was looting and widespread vandalism, Kyrgyz officials said. The rioting lasted throughout the night and most of the next day.

Extra army and police units have been dispatched, a state of emergency has been declared and a 6 p.m.-to-6 a.m. curfew has been imposed in several districts of southern Kyrgyzstan until June 20, the government announced.