Four convicts are on the run after killing a police officer and breaking out of prison in suburban Hohhot, capital of the Inner Mongolia autonomous region.

The four hijacked a taxi and escaped after kidnapping and killing one officer and injuring a worker at Hohhot's No 2 prison around 2:30 pm on Saturday, according to Yan Bingqiang, deputy chief of police of Inner Mongolia.

When the taxi ran out of gas, the escapees hijacked another cab and headed toward downtown Hohhot, Yan said.