A suspected car bomb exploded in a car park in central Madrid last night, slightly injuring 14 people close to a spot where King Juan Carlos had attended a military parade earlier in the day, officials said.
Madrid's mayor, Mr Jose Maria Alvarez del Manzano, said it was too early to say whether the explosion was the work of Basque separatist group ETA.
But police officers at the scene said the blast had the hallmarks of an ETA attack.
The explosion in the underground car park in the Plaza de Colon square blew a hole through one of the floors, sending the car plunging to the floor below, the mayor told reporters after visiting the scene with firefighters this morning.
Mr Del Manzano said two people appeared to have suffered a broken collarbone and a leg injury. The rest of the injuries are serious, he said.
A fire brigade officer said 14 people had been treated for injuries, none of which were life-threatening.
Earlier yesterfday, King Juan Carlos, Prime Minister Jose Maria Aznar and other political leaders sat in a temporary grandstand in the Plaza de Colon to watch a military parade marking a Spanish national holiday.