A bomb blast in Madrid on Saturday claimed no casualties, but it may have dealt a bitter blow to the city’s hopes of hosting the 2012 Olympics. An explosion rocked the car park of a sports stadium at the centre of the Spanish capital’s bid. It comes less than two weeks before the International Olympic Committee makes its final decision. A warning in the name of the armed Basque separatist group ETA preceded the blast. Spain’s government has offered to hold peace talks with ETA, but only if the terror group lays down its arms.