MADRID (Reuters) - A powerful bomb hidden inside a backpack exploded outside a courthouse in Spain's Basque region in the early hours of Friday and police suspected it was the first attack of 2008 by Basque separatist guerrillas ETA.
The explosion in the town of Bergara, around 100 km (62 miles) southwest of coastal resort San Sebastian, caused considerable damage to the courthouse and nearby shops and vehicles, but there were no injuries.
"We suspect ETA was behind this," said a police spokesman.
Emergency authorities received a warning call that a bomb had been planted and security guards were evacuated after the backpack was discovered.
It was not the first attack on the courthouse in Bergara, a town run by Basque political party ANV, which is in the process of being banned for alleged links to ETA.
The attack followed the arrest on Monday of the two most senior leaders of banned Basque separatist party Batasuna.
Spain's Socialist Prime Minister Jose Luis Rodriguez Zapatero, fighting to retain office in a March general election, faces criticism over failed ETA peace talks and has launched a crackdown on the Basque separatist rebels and their allies.
ETA has killed more than 800 people during its four decade campaign for an independent Basque state.
The most recent deaths were in December, when ETA guerrillas shot dead two undercover Spanish policemen in southern France.
(Reporting by Inmaculada Sanz, Andrew Hay; Editing by Catherine Evans)