In a videotaped message, a man purporting to represent al-Qaida claims the terrorist network was behind bombings that killed 200 and wounded 1,500 in Madrid, the Spanish interior minister said Saturday.

The tape -- along with the arrest of three Moroccan and two Indian suspects -- provide the strongest indication yet of a possible Islamic link to the attack on one of Washington's staunchest allies in Iraq. The Spanish government, however, said it could not confirm the tape's authenticity.

The announcement by Interior Minister Angel Acebes came just hours before polls were to open Sunday in general elections weighed down by debate over who carried out the attack.

"We declare our responsibility for what happened in Madrid exactly 2 1/2 years after the attacks on New York and Washington," said the man, according to a government translation of the tape, which was recorded in Arabic. "It is a response to your collaboration with the criminals Bush and his allies."

Prime Minister Jose Maria Aznar has been a staunch supporter of the US-led war in Iraq.

A London-based Arabic newspaper had earlier received a claim of responsibility in al-Qaida's name; but the government has been reluctant to blame the Islamic group, saying the Basque separatist group ETA was also a suspect. ETA denied responsibility.

Speaking at a hastily called post-midnight news conference at the Interior Ministry, Acebes said authorities could not confirm the claim was genuine. He said the videotape was discovered after an Arabic-speaking man called a Madrid TV station and said where it could be found.

A statement from the ministry said the speaker was identified as Abu Dujan al Afghani. Acebes said he claimed to be the military spokesman of al-Qaida in Europe, but said he was not known to law enforcement authorities in Spain, and that they were checking the tape's authenticity.

The man threatened further attacks in the video.

"This is a response to the crimes that you caused in the world, and specifically in Iraq and Afghanistan, and there will be more if God wills it," the man said, according to the Spanish government's translation.

Thursday's attacks in Madrid came just days before Sunday's general elections in Spain. At demonstrations Saturday, some protesters said they believed the ruling party was playing down the possible link between the bombings and Spain's role in Iraq, fearing it would hurt the party's chances in the election.

About 5,000 people protested Saturday outside the ruling party headquarters in Madrid, holding up signs saying "no more cover-up."

One banner read: "Aznar, because of you we all pay."

"Maybe now the truth will come out," Fernando Hernandez, a college student, said after hearing about the arrests. "All we want is the truth."

Earlier Saturday, Acebes said the five suspects were arrested around Madrid. A spokesman for the Moroccan government identified the three Moroccans as Jamal Zougam, 30; Mohamed Bekkali, 31, a mechanic; and Mohamed Chaoui, 34. All three are from northern Morocco, but the government gave no further details about them.

"One might have connections with Moroccan extremist groups. But it is still very early to establish to what degree," Acebes said. He did not name any group.

The five suspects were arrested after a gym bag packed with explosives and a cell phone was discovered on one of the four bombed rush-hour trains, the minister said. The attacks killed 200 people and injured 1,500.

 Two Spaniards of Indian origin also were called for questioning but are not expected to be arrested, Acebes said.

Spanish citizens were among 33 people killed by suicide bombings that targeted Jewish targets and a Spanish restaurant close to the Spanish Consulate in Casablanca, Morocco in May 2003.

Those attacks were blamed on Salafia Jihadia, a secretive, radical Islamic group thought by Moroccan authorities to have links to al-Qaida. Twelve suicide bombers also died.

Just months ago, a taped threat thought to be from al-Qaida terror chief Osama bin Laden had included Spain among countries that could be attacked "at the appropriate time and place."

A confirmed Islamic extremist involvement in the Madrid bombings could play into the hands of Aznar critics who opposed sending 1,300 peacekeepers to Iraq.

"If it was al-Qaida, this was a reprisal for sending troops to Iraq, where we have no business being," said Damian Garcia, whose 86-year-old father died in the bombings.

The government had sought to dampen such speculation. Acebes said earlier Saturday that autopsies conducted on victims showed no signs of suicide bombings -- a hallmark of Islamic militants.

Pressure mounted for answers. The crowd outside the Popular Party headquarters chanted, "We want the truth before voting."

Aznar's hand-picked candidate to succeed him, Mariano Rajoy, charged that the rally violated a law banning political demonstrations on the day before an election.

"I hereby demand that the organizers of this illegal demonstration end this antidemocratic act of pressure against tomorrow's elections," he said.

Hours earlier, the opposition Socialists charged that Rajoy himself violated the law by urging voters in a newspaper interview Saturday to give an absolute majority in the Parliament.

Rajoy was only 3-5 percentage points ahead of Socialist candidate Jose Luis Rodriguez Zapatero before opinion polls were stopped before the blasts in the last week of campaigning.

The massive police hunt for the bombers focused in part on a stolen van found with seven detonators and an audiotape of verses from the Quran. A witness told Associated Press Television News he saw three suspicious men go from the vehicle to a station where three of the four bombed trains originated.

The men wore coverings on their faces but "it wasn't cold ... I thought it was very strange," said the man, who did not want to be named. "They went into the train station ... I tried to follow one of them but I couldn't because he was very fast."

The attack's lethal coordination -- 10 explosions within 15 minutes -- pointed to al-Qaida.

The compressed dynamite used in the attacks, however, is favored by ETA, which has killed more than 800 people in four decades of bombings and assassinations to carve out an independent Basque homeland in northern Spain.

ETA attacks have never been as deadly as the Madrid bombings and mostly targeted police and politicians. On Friday, a caller claiming to represent ETA told a Basque newspaper it was not responsible -- the first time ETA is known to have denied an attack.

The death of a man in a hospital overnight pushed the toll up to 200 Saturday. Of the 1,511 injured, 266 remained hospitalized -- with 17 in critical condition.

Since the Sept. 11, 2001, attacks in the United States, only the Bali bombing in Indonesia in October 2002 was deadlier, with 202 people dead. The Madrid attack was Europe's deadliest since the 1988 bombing of a Pan Am jetliner over Lockerbie, Scotland, killed 270 people.

A steady stream of hearses carried coffins in and out of Madrid's biggest funeral home, Tanatorio Sur. The sprawling red-brick building normally has plenty of room, but was still overwhelmed Saturday. For lack of space, the coffins of a couple killed in the attacks were placed in a room normally used for staff meetings.

"My son. Why?" repeatedly sobbed one elderly woman, leaning on relatives.

(China Daily March 14, 2004)