A car bomb blamed on Basque separatists (search) exploded in a Madrid office park Wednesday near where King Juan Carlos later appeared, injuring at least 43 people in the worst terrorist attack in the Spanish capital since last year's bombing of commuter trains.
The bomb exploded at about 9:30 a.m., less than an hour after a warning call purportedly made by the Basque separatist group ETA (search). It shattered thick panes of glass in buildings — spraying shards over a wide area — and damaged cars.
Police did not have time after the call to the Basque newspaper Gara to fully cordon off the area or fully evacuate workers and visitors at the sprawling convention center nearby, where the king later met Mexico President Vicente Fox (search) to inaugurate an art show that includes Mexican works.
The latest bombing came hours after police arrested 14 suspected members of ETA and a week after Spain's Parliament overwhelmingly rejected a plan giving the Basque region broad autonomy bordering on independence.
In recent years, police have weakened the separatists with arrests, but the bombing is a reminder they retain the ability to use violence.
The bomb detonated near a plaza with a large bust of the king's late father, Juan de Borbon, and outside a building housing the French computer manufacturer Bull.
The bomb used an estimated 66 pounds of explosives, Interior Minister Jose Antonio Alonso said. It was the worst blast in Spain's capital since the March 11 train bombings that killed 191 people and were claimed by militants saying they acted on behalf of Al Qaeda.
A witness identified only as Daniel said in a televised interview that the bomb shook his car as he drove about 100 yards away from the blast site.
"It was an extremely powerful explosion," he said.
Another witness, Bull communication director Manuel Amenteros, told The Associated Press he was in a first-floor office about 20 yards from the bomb when it exploded.
"What saved me — from the force of the blast and from flying glass shards — was my computer," he said.
The injured suffered bruises, cuts from flying glass and damaged eardrums, said Javier Ayuso, spokesman for the Madrid emergency medical service. No one was seriously hurt, he said.
Prime Minister Jose Luis Rodriguez Zapatero denounced the bombing.
"ETA and those who support it have no place in political or civil life. Bombs lead only to jail," he said during a visit to Poland.
ETA is blamed for more than 800 deaths since the late 1960s in a campaign of bombings and shootings aimed at creating an independent Basque homeland in land straddling northern Spain and southwest France. Its political wing, Batasuna, was outlawed in 2003.
The Interior Ministry said 14 ETA suspects were arrested Tuesday in all three Basque provinces plus areas in northern, eastern and southern Spain.
The suspects were involved in recruiting new members, supporting existing commandos and gathering information on potential targets for attack, the ministry said in a statement.
ETA detonated a small bomb in a Mediterranean resort hotel Jan. 30, two days before the vote against broader autonomy. One person was slightly injured.
ETA carried out a string of small bombings in northern resort towns over the summer. It also detonated seven bombs around Spain on Dec. 6 — the anniversary of Spain's 1978 constitution, which set up the system of regional autonomy that ETA abhors as insufficient.