Spanish protests condemn ETA

A bystander walks past wreckage from the blast in Madrid on Tuesday

MADRID, Spain (CNN) -- Thousands of Spaniards have taken to the streets in protest at the latest killing blamed on the armed Basque separatist group ETA.

Spaniards stood outside government buildings across the country at noon on Wednesday to demonstrate against the killing of a policeman who died while responding to a bomb alert in Madrid the previous evening.

Hundreds of further demonstrations are planned for Wednesday evening.

Politicians attending the opening of the Basque parliament held a minute's silence before a debate on the swearing in of moderate nationalist regional president Juan Jose Ibarretxe.

CNN's Al Goodman the bomb was intended to send a message to the Basque parliament.

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The parliament has vowed to continue to work for an end to ETA attacks, but the seven members of the pro-ETA political party Euskal Herritarrok entered the chamber 10 minutes into the session, missing the tribute.

Ibarretxe, leader of the Basque Nationalist Party, said: "ETA is the enemy of the (Basque) country and the country has to respond in a united fashion in order to defend its freedoms.

"We have overcome serious challenges in the economic and social areas. Now we must achieve lasting peace, and I commit myself to finding a solution to the so-called Basque problem."

Spanish Prime Minister Jose Maria Aznar, along with other dignitaries, were among the mourners at the policeman's funeral on Wednesday morning.

The 33-year-old policeman, Luis Ortiz de la Rosa, died while trying to close off the area in a southern suburb of the capital following a bomb warning.

The national anthem was played as the coffin of Ortiz, a father of a 17-month-old girl, was carried from the government building where the ceremony was held.

No group has so far claimed responsibility, but the explosion bears the hallmark of ETA.

Spanish Interior Minister Mariano Rajoy said the latest bomb attack in Madrid indicated that ETA was operating a special unit in the capital and he pledged to tighten security.

Another car bomb was set off on the eve of Basque elections on May 13 in which the radical party linked to ETA suffered a heavy defeat, losing nearly half its seats as its share of the vote plunged to about 10 percent, a fall of 8 percent on its previous election return. ETA is blamed for about 800 killings in its 33-year fight for independence, including 32 deaths since it called off a unilateral cease fire in December 1999.

The group has not claimed responsibility for all of those killings. When ETA claims responsibility for attacks, it typically does so in the Basque media, sometimes days or weeks after the attacks occur.

The most recent attack blamed on ETA was on June 28, when a bomb hidden in bicycle in Madrid was exploded by remote control, injuring an army division commander