A car bomb has exploded outside a police barracks in northern Spain, in an attack that police said is supected of being carried out by the separatist Eta group which ended a ceasefire in June.

Two police officers were wounded in the blast early on Friday at the Guardia Civil barracks in the town of Durango in the Basque region.

"Everything indicates it is Eta," a police spokesman said.

There was no immediate claim of responsibility or warning issued before the attack.

The bomb, which was in a van parked outside the barracks, caused considerable damage to the building, shattering windows and damaging police cars.

Several residential buildings were also damaged.

An hour after the blast a burnt-out car was found in the nearby town of Amorebieta, which Basque police said may have been used by the bomber.

Arrests

The blast came after Alfredo Perez Rubalcaba, interior minister, warned that an Eta attack was imminent.

Recent weeks have seen the arrests of a number of suspects, mainly in France, and 400 kilos of explosives seized.

The group has been blamed for 819 killings in its 40-year campaign for an independent Basque state.
  
Eta had declared a "permanent ceasefire" in March 2006, but then claimed responsibility for the bombing of Madrid airport on December 30, 2006 which killed two Ecuadoran men.

The government called off peace talks with the group after the airport bombing and the separatists formally declared the ceasefire over in June this year.