Spanish authorities say a blast which killed two people in the northern city of Bilbao may have been the result of a bungled attack by the armed Basque separatist group, ETA.

Spanish and French police are co-operating on arrests

Officials said two bodies were found in the wreckage of a car which exploded at 2340 (2140 GMT) on Monday in the suburb of Mazustegi.

Bilbao's mayor, Inaki Azkuna, said radio control equipment, false number plates and a pistol had been found in the wreckage.

No one else was injured by the blast, and no claim of responsibility has yet been made.

Bilbao, in the Basque region, has witnessed many bombings carried out by ETA.

Police are investigating the possibility that the two victims were separatist activists who had been about to plant a bomb.

"It seems they were preparing a limpet bomb or a car bomb," said Mr Azkuna.

Nine arrests

The Spanish Government has vowed to crack down on violence in the Basque region.

Last month, it banned the radical Basque political party Batasuna, which it says is linked to ETA.

On Monday, an ETA suspect, 53-year-old Jose Luis Kamiode, was detained, the ninth such arrest in the past week.

Basque militants reject the government crackdown

After a unilateral ETA truce collapsed at the end of 1999, the crackdown has also taken the form of closer co-operation between Spanish and French police, which has brought some 20 arrests so far this year in France.

Last week Spain announced the arrest of what it described as two top ETA leaders, in a police operation in southern France.

ETA has killed more than 800 people and injured some 2,300 others since 1968 in its campaign for an independent Basque homeland in a region that spans northern Spain and south-western France.