A car bomb exploded outside a Madrid stadium that is the centrepiece of the city's 2012 Olympic Games bid, after a warning from ETA. The blast caused minor damage and no injuries.
The explosion in the car park of La Peineta stadium occurred less than two weeks before a decision is due to be announced on whether Madrid or one of four other candidate cities will stage the 2012 Olympics. The stadium, which is being expanded to hold 76,000 spectators, will host the opening and closing ceremonies and athletics events if Madrid is awarded the Games.
"They want to damage Madrid's interests at a very significant time for our city, when the nomination to host the 2012 Olympic games is at stake," Rafael Simancas, leader of the Socialist Party in Madrid said.
Interior Minister Jose Antonio Alonso condemned the attack, saying the "security forces will continue working with all firmness until they bring about the definitive end of ETA".
The explosion followed a warning call in the name of ETA to the Basque language newspaper Gara. Police had enough time to clear the area before the bomb, placed in a stolen car, went off.
The blast occurred on the day that the Basque region's nationalist premier, Juan Jose Ibarretxe, was sworn in for a new term.
ETA, classed as a terrorist group by the European Union and the United States, has killed nearly 850 people since 1968 in a violent campaign for an independent Basque state in northern Spain and southwestern France.
The Spanish capital is vying with Paris, New York, London and Moscow for the Olympics. A final decision will be taken in Singapore on July 6 thand security at the Games has been a priority for the International Olympic Committee.