Premier Jose Luis Rodriguez Zapatero, testifying before a parliamentary commission, stopped just short of accusing the conservative Popular Party, in power at the time, of lying for electoral gain about the attacks that killed 191 people.

The investigation showed Islamic militants were responsible, not Basque separatist guerrilla group ETA as former Prime Minister Jose Maria Aznar had initially insisted.

"It was all deceit. It was massive deceit," said Zapatero, using unusually harsh words for a head of government.

Aznar had no immediate response but has repeatedly denied the government lied about the attacks, saying he blamed ETA based on what police and intelligence services told him.

But Zapatero said the previous government had no objective reason to blame the attacks on ETA as of the afternoon of the attacks but kept doing so right up to midnight before the March 14 vote.

"Today we know objectively that there was not a single piece of data pointing to ETA," Zapatero said, adding that what little there was -- about the type of explosives used -- turned out to be false and was cleared up by midday of the attacks.

The bombers issued a videotape on election eve calling the attacks revenge by al Qaeda for Spain sending troops to Iraq (news - web sites) and Afghanistan (news - web sites).

Aznar defied public opinion by backing the U.S. invasion of Iraq and sending in Spanish troops after the fall of Saddam Hussein (news - web sites).

This was seen as a factor in the Socialists' upset election victory over Aznar's hand-picked successor.

COMPUTER RECORDS ERASED

Zapatero, the first Spanish prime minister to be questioned by a parliamentary investigation, said the Aznar government erased all computer records about events between March 11 and March 14.

"There was a massive erasing (of computer records) ... There is nothing from March 11 to March 14 in the prime minister's office," Zapatero said. But, he added, "they did leave us the bill for the massive erasing."

El Pais newspaper reported the job cost 12,000 euros ($15,940).

Zapatero made good on a campaign pledge and ordered the troops home from Iraq immediately after taking office in April, which critics labeled as appeasement.

"I withdrew the troops from Iraq because I always said the war was illegal and because the majority of the citizens clearly and resoundingly rejected it (the war). ... No Spanish government has knelt before terror and none ever will kneel. Each blow reaffirms our values," Zapatero said.