Beijing:At least 30 persons were killed after a tour bus burst into flames in Hunan province of China on Sunday morning, authorities said. The accident happened around 10.20 a.m. (local time) when the bus carrying 56 persons crashed into the guardrails on a highway in Yizhang county, Xinhua news agency reported. The oil leak after then crash may have caused the fire, a government official said. At least 21 people were rushed to hospitals, and rescuers were still searching the charred frame of the bus. The police has detained the driver, the official said.