ETA bomb explodes in northern Spain, no injuries: police

MADRID (Reuters) - A bomb exploded outside a courthouse in northern Spain on Sunday, two days after Basque separatists ETA said they would continue to strike Spanish government forces.

Basque police said there were no injuries after they received a warning call from ETA at about half past midnight (6:30 p.m. EST) and cleared the area, including two bars, before the package exploded.

The doorway and the ceiling of the courthouse in Sestao, northwest of Bilbao, were damaged, the police said, adding that the bomb was made up of two or three kilograms of explosives stuffed in a plastic bag.

ETA has killed more than 800 people in the last four decades as they fight to separate the Basque country from France and Spain.

Two weeks ago, they shot dead two plain clothes policemen who were tracking down ETA members in France and on Friday the group issued a statement warning they would continue to act against "the forces and repressive apparatus of the Spanish state, wherever it may be."

Spanish police have arrested dozens of ETA members this year after calling off peace talks when the guerrillas blew up a car park at Madrid airport, killing two people.

(Reporting by Jane Barrett; editing by Elizabeth Piper)