At least 23 people have been killed in clashes in Kyrgyzstan's second-largest city of Osh. Officials said more than 300 people were injured when hundreds of youths fought in the streets of the southern city. More than 40 were reported to be in a serious condition. According to local reports, fighting broke out between rival gangs and developed into gun battles late on Thursday. A state of emergency has been declared. Armoured vehicles are in the city and officials say calm had been restored. Interim President Roza Otunbayeva said that security forces had brought the situation under control but that the situation remained tense. She said those responsible for the violence were trying to destabilise Kyrgyzstan and plunge it into fighting or conflicts. She called on people to show restraint and not yield to provocations. The leaders of Russia and China have appealed for calm.