A civil guard is on duty while emergency services wait to evacuate the wounded at a Civil Guard barracks on the Spanish island of Majorca.
Police in Spain are on heightened alert after two bomb attacks in 48 hours blamed on the Basque separatists, Eta, the BBC reported.
On Thursday, two Civil Guard officers were killed when a car bomb exploded outside a base in the resort town of Palmanova on the island of Majorca.
Another car bomb blast on Wednesday destroyed much of a police barracks in the northern city of Burgos and left more than 50 people slightly wounded.
The attacks coincide with the 50th anniversary of Eta's founding.
They also come at a time when police resources are stretched because of the start of the holiday season.
Following Thursday's bombing, the authorities temporarily closed ports and airports on Majorca as part of a security operation to prevent those responsible from escaping, causing travel chaos for tourists.
Eta has been held responsible for more than 820 deaths during its campaign for an independent homeland in Spain's Basque region.