At least 37 people were killed and more than 500 wounded during overnight violence in southern Kyrgyzstan.

The ethnic conflict flared in Kyrgyzstan's second-largest city of Osh.

It is the worst outbreak of violence in the Central Asian state since the president was overthrown in April.

The interim government in Kyrgyzstan declared a state of emergency in Osh and several local rural districts after hundreds of youths battled with guns and steel bars, setting shops ablaze in the city.

The government, led by Roza Otunbayeva, sent troops and armoured vehicles to quell gangs roaming the streets.

'Destructive forces, together with criminal elements, are trying to escalate inter-ethnic conflict,' Ruslan Kazakbayev, the country's interim foreign minister, said during a summit of regional leaders in neighbouring Uzbekistan.

The leaders of Russia and China have called for calm in Kyrgyzstan.

President Dmitry Medvedev told the summit that Russia wanted a swift end to the unrest in neighboring Kyrgyzstan, a country that hosts both US and Russian military bases.

'We hope there will be a swift stabilisation of the situation in Kyrgyzstan,' Chinese President Hu Jintao said through a Russian translator.

'China continues to help Kyrgyzstan as much as it can.'