HOHHOT - A fire raging through a prairie in Mongolia spread across the country's southern border into China on Friday, prompting authorities to send hundreds of firefighters to combat the blaze.

A fire crossing two sections of the China-Mongolia border has engulfed six square km of grassland in North China's Inner Mongolia autonomous region, said a spokesman from the regional government, citing information from satellite images obtained by the regional meteorological bureau at 7 pm Friday.

More than 580 firefighters have rushed to the border to work with Mongolian firefighters to put out the fire, the spokesman said.