European Commission President Jose Manuel Barroso condemned the early morning attacks, which destroyed the façade of the barracks and gouged a seven-meter-wide (23 feet) hole in the ground.

"I want to express our firm condemnation of the attack on the Civil Guard barracks in Burgos," he said in a statement. "I want to express the European Commission's complete solidarity with the citizens and the democratic institutions of Spain in the fight against terrorism."

Of those injured, including several children, none sustained serious injuries.

While there was no warning call, typical of ETA attacks, and no group has claimed responsibility for the bombing, authorities are blaming the Basque separatist group.

Miguel Alejo, the Spanish government delegate for the Castile and Leon community said the attack appeared to be "like those that the ETA killers carry out." ETA has often targeted the Civil Guard, the Spanish gendarmerie.

ETA, which was founded on July 31, 1959, has been blamed for the deaths of about 850 people since its campaign for an independent Basque nation in northern Spain and southern France turned violent in 1968.

In mid-2007, the group called off a 15-month ceasefire after tentative peace talks with Madrid faltered. Since then Prime Minister Jose Luis Rodriguez Zapatero's Socialist government has taken a hard line against ETA with targeted police operations seeking to weaken its leadership.

The most recent killing blamed on ETA was the June 19 death of a police inspector, who was killed in a car bomb attack in the northern city of Bilbao.

Both the United States and the European Union consider ETA to be a terrorist organization.

hf/AFP/dpa
Editor: Neil King