Madrid, July 28 (DPA) Up to 37 people were injured when a car bomb exploded outside police barracks in Burgos in northern Spain Wednesday morning, the El Mundo newspaper said in its internet edition.

The car bomb exploded around 4 a.m. (0200 GMT) next to a building occupied by Spain's Guardia Civil, the paper said, quoting police sources.

There had been no warning. Police suspect the Basque separatist group ETA may have been responsible for the bombing.

Most of the victims suffered only light injuries, mainly cuts from broken glass, but damage to the buildings was substantial.

The vehicle containing the bomb was parked behind a house in which policemen and their families were sleeping, Cadena radio said.

The explosion caused panic, the report said

Police believe a van stolen in France was used for the attack.