Investigators gesture beside the wreckage of a car near Palma, on the island of Mallorca, on Thursday. (Dani Cardona/Reuters)

A bomb blast outside a police barracks in the Spanish island of Mallorca Thursday killed two officers, and authorities conducted a controlled explosion of a second bomb in the vicinity shortly afterwards.

The explosion rocked police barracks in the Palmanova beach resort, southwest of the island's capital, Palma de Mallorca. Television images showed the charred and mangled remains of a vehicle that had been parked on a street in the area.

The Associated Press quoted a Madrid police spokesman as saying the second, undetonated, bomb was under a police jeep in the vicinity of the blast.

Two officers, aged 26 and 27 and belonging to Spain's Civil Guard paramilitary service, were killed in the afternoon explosion.

That blast came a day after a similar attack in northern Spain injured dozens.

Spanish Interior Minister Alfredo Perez Rubalcaba has blamed Basque separatist group ETA for both bombings.

Possible car bomb

Thursday's explosion was caused by a bomb attached underneath the vehicle, Interior Ministry official Ramon Socias said. Police believe the attack was carried out by an ETA cell that came to the island specifically to carry it out and was not based there, he said.

Smoke and flames rise from a car following an explosion in the Palmanova beach area, southwest of the island's capital, Palma de Mallorca, Spain, on Thursday. (Liam Oliver/Associated Press)

In the immediate aftermath of the attack, security forces sealed off the island "to avoid the escape of the terrorists," said a regional Interior Ministry statement.

"This means that all exit routes via the port, the airport and the sports marinas of Mallorca are closed," the statement said.

The airport and ports were later reopened.

Several injuries

The Interior Ministry said several people were injured in the Thursday blast, but none were in serious condition.

Police have identified a car bomb as the cause of Wednesday's attack, in which an explosion rocked another Civil Guard barracks in the northern city of Burgos, injuring at least 60 people.

If confirmed as ETA attacks, the blasts would conflict with government assertions that the group is seriously weakened after major police crackdowns in Spain and France in recent years.

ETA has killed more than 825 people since it launched a campaign in 1968 for an independent homeland in the Basque region of northern Spain.

ETA is a Basque-language acronym for Basque Homeland and Freedom.

With files from The Associated Press