A car bomb exploded Saturday, killing at least six police officers riding by on their way to a soccer game, police said. Basque separatists were suspected in Spain's deadliest attack in three years.

At least eight people, including two policemen, were injured in the blast in the industrial town 12 miles north of Barcelona, said police spokeswoman Maria Luisa Pena.There were no claims of responsibility for the bombing, the deadliest in Spain since a December 1987 attack outside a Civil Guard barracks in Zaragoza that killed 11 people.

But police said it appeared to be the work of ETA, the Basque separatist organization that has claimed responsibility for 18 killings so far this year.

A Sabadell policeman said a booby-trapped car blew up about 1,500 feet from a police station, just as the van was riding by.

The police were on their way to handle security at a second-division soccer match in the Nova Creu Alta stadium. Some of the soccer playoffs in the Barcelona Summer Olympic games in 1992 are to be played in the stadium.

The match between Sabadell and Malaga went ahead as scheduled with a minute of silence for the victims before play began.

Spanish police said four suspected ETA members who were arrested in southern France on Nov. 17 were carrying papers and documents indicating the group planned to set up operations in Barcelona to attack Olympic targets.

Last week, specialists from more than 20 countries met in Barcelona to discuss security at the games.