A bomb blast in the northern Spanish city of Bilbao has left at least one person wounded.

Police say the bomb went off Tuesday under a parked car in the city, which is located in Spain's Basque region.  They identified the victim as the bodyguard of a local politician and member of Spain's ruling Socialist party.

There was no immediate claim of responsibility for the bombing.  But it happened several days after authorities arrested 23 members of the Basque party, Batasuna, during a meeting in the town of Segura.  Seventeen of the detainees remain in custody.

Batasuna is the banned political wing of the armed Basque separatist group, ETA.

Spanish authorities recently have increased security ahead of celebrations of the country's National Day Friday.

ETA has been fighting a nearly 40-year guerrilla war for creation of an independent Basque state in northern Spain and southwestern France.  That war has killed more than 800 people.

The group recently called off a cease-fire, accusing the Spanish government of doing little to reach a peace settlement.

Some information for this report was provided by AFP, AP and Reuters.