MADRID, Spain (CNN) -- A bomb wounded a local politician's bodyguard in the northern city of Bilbao on Tuesday, in an attack a senior Interior Ministry official blamed on the Basque separatist group ETA.
Basque policeman at the scene of Tuesday's car bomb in the northern Spanish Basque city of Bilbao.
The bomb exploded as the off-duty bodyguard was alone in his car and was just starting to move it, said the official, Antonio Camacho, the secretary of state for security.
Police, he added, suspect the explosive may have been a limpet bomb, attached beneath the car toward the rear.
"It seems clear ETA wanted to kill someone. We can't yet say if the target was the bodyguard or the politician he protects," Camacho said at a nationally televised news conference.
The guard, Gabriel Gines, 36, was taken to hospital with burns to his face, right hand and shoulder, Camacho said.
Witnesses said he managed to get out of the car after the blast. Television footage showed him walking out of a nearby cafeteria, where he had taken refuge, and stepping into an ambulance, flanked by emergency workers. His right hand was bandaged and his left hand held a cell phone.
There was no warning call -- as sometimes occurs -- before the explosion near downtown Bilbao, the largest Basque city, an Interior Ministry spokesman told CNN.
No one has claimed responsibility for the incident, which left the bodyguard's car and several others charred from fire.
Several thousand town councilors and other officials in the Basque region have bodyguards due to threats from ETA, which is blamed for more than 800 deaths in its long fight for Basque independence. Many of the bodyguards are police officers; others, such as the guard injured on Tuesday, are on contract from private security firms.
The politician he protects, a Basque local councilman from the prime minister's ruling Socialist Party, was out of town at the time of the attack.
The blast came shortly after Interior Minister Alfredo Perez Rubalcaba announced at a news conference in Madrid that police were stepping up security this week because of fears of more ETA attacks. Friday is a Spanish holiday.
Last week, police arrested 23 leaders of an outlawed Basque pro-independence party, Batasuna, on suspicion of aiding ETA. On Sunday, a judge remanded 17 of them to jail, released four on bail and dropped charges against the other two. Watch how arrests make ETA defensive »
Batasuna is widely considered to be ETA's political wing, which it denies. The arrests were seen as part of broad crackdown on ETA and its supporters after ETA formally called off its cease-fire last June.
ETA is listed as a terrorist group by the United States and the European Union.
The most recent fatalities were last December, when a massive ETA car bomb killed two men at Madrid's airport, destroying a parking garage and causing heavy damage to the airport's newest glass-covered passenger terminal.
That blast, preceded by a warning call, came during the unilateral cease-fire, which ETA announced in 2006. ETA had promised the cease-fire would be "permanent," raising hopes for a lasting peace.
The Socialist government considered ETA's cease-fire over after the airport bombing and halted all peace contacts. Since ETA officially ended the cease-fire last June, it has managed only one major bombing before Tuesday, while several other intended attacks were thwarted by police.
Police in Spain and France have arrested dozens of suspected ETA members, including senior operatives since June. E-mail to a friend
All About ETA Separatist Group
A bomb wounded a local politician's bodyguard in the northern city of Bilbao on Tuesday, in an attack a senior Spanish Interior Ministry official blamed on the Basque separatist group ETA.

Spanish media say the injured man is a bodyguard for a town councillor from Spain's ruling Socialist Party, who was taken to hospital with burns to his face, right hand, and shoulder.  While there was no immediate claim of responsibility, Basque regional government sources said the attack bore the hallmarks of an attack by the armed separatist group ETA.

It comes days after suspected leaders of the separatist party Batasuna were arrested, an action the party described as a "declaration of war".