A powerful bomb exploded outside a courthouse in Spain's Basque region early today.
The explosion in the town of Bergara, around 100 kilometres southwest of San Sebastian, caused damage to the courthouse and nearby shops and vehicles.
Police suspect Eta was behind the bomb, which was hidden inside a backpack.
A warning call was received that a bomb had been planted, and security guards were evacuated after the backpack was discovered.
The town of Bergara is 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.
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 the organisation shot dead two undercover Spanish policemen in southern France.