Who's Behind Madrid Bombings?

Spanish leaders were quick to accuse Basque terrorists for setting off Thursday's devastating attacks in Madrid.

But hours later they were less sure. A shadowy Muslim militant group claimed responsibility in the name of al Qaeda and a van found near the attacks had detonators inside plus tapes of Quranic versus.

Getting at the truth could take time. Spanish officials used to blaming terrorism on the Basque separatist group ETA said they were opening up several lines of investigation. As recent events have shown, it won't be easy. Other terrorist attacks carried out in the past two years in places such as Morocco and Turkey remain unsolved.

In Washington, a U.S. counterterrorism official, speaking on condition of anonymity, said it was too early to determine who was responsible for the attacks which killed more than 190 people and wounded over 1,000.

"We're not ruling out the possibility there was outside responsibility (beyond ETA) in this," the official said. "That's something being pursued, but at this point it's too early to tell."

If ETA was behind the 10 bombs that tore through trains and stations around Madrid, it would mark a stunning turning point for the group.

For years ETA relied on targeted killings, extortion and kidnappings to press for an independent homeland straddling parts of Spain and France. Now experts believe a younger generation of ETA leaders is moving the group toward al Qaeda-style actions.

"You've lost the old guard who were very reticent about killing larger numbers of people because they think that will not help their cause," said Mia Soar, a European terrorism analyst for Jane's Information Group in London. "Then you have this new, younger cadre who've been trained in urban violence who don't think like that."

Spain's Interior Minister Angel Acebes said ETA tried a similar attack on Christmas Eve, placing bombs on two trains bound for a Madrid station that was not hit Thursday. He also noted the Feb. 29 police interception of a Madrid-bound van packed with more than 1,100 pounds of explosives. Thursday's bombers used titadine, a kind of compressed dynamite also found in the van intercepted last month.

But a top Basque politician, Arnold Otegi, denied the separatists were behind the blasts and blamed "Arab resistance."

Otegi told Radio Popular in San Sebastian that ETA always phones in warnings before attacking. Acebes said there was no warning Thursday.

A top French anti-terrorism official said a "small door" must be left open for the possibility that Islamist radicals were behind the carnage.

"There are still not enough elements to say 100 percent that it was ETA," said Gilles Leclair, director of France's Anti-Terrorism Coordination Unit.

Claude Moniquet of the European Strategic Intelligence and Security Center in Brussels said the attack bore some hallmarks of Muslim militancy.

"Multiple targeting is very, very specific to al Qaeda," he said. Prior examples include the attacks against the U.S. Embassies in Kenya and Tanzania in 1998 and the Sept. 11, 2001, attacks in the United States.

Spain has been named in recent al Qaeda communiqués because of its strong relationship with the United States and its support for the war in Iraq. It was also a close partner in the war on terrorism, arresting al Qaeda suspects in Spain and helping to dismantle militant networks targeting the United States.

The Arabic newspaper Al-Quds al-Arabi said Thursday it had received a claim of responsibility for the Madrid bombings issued in the name of al Qaeda.

The five-page e-mail claim, signed by a group known as the Brigade of Abu Hafs al-Masri, was received at the paper's London offices. It said the brigade's "death squad" had penetrated Spain.

"This is part of settling old accounts with Spain, the crusader, and America's ally in its war against Islam," the claim said.

The United States believes the group, which takes its name in memory of al Qaeda's fallen No. 3, lacks credibility and its ties to al Qaeda are tenuous. In the past, the group has made claims to various events which they weren't connected to such as blackouts last year in the United States and Canada and in London.

Yonah Alexander, a counterterrorism expert in Washington, said there was no evidence ETA had a relationship with al Qaeda but it had shared information with Palestinian militants.

"They have a link with Palestinian groups and they use some of the money from kidnappings and extortion to support those groups in the West Bank and Gaza. In return ETA gets information, intelligence, weapons and a piece of narco-trafficking. It's strictly a resource-sharing relationship, there's no ideological base between them."

The attack on Spain sent a chill throughout Europe.

Paul Wilkinson, chairman of the Centre for the Study of Terrorism and Political Violence at the University of St. Andrews in Scotland, said Spain could face more bloodshed as elections approach.

"I'm sure the Spanish authorities are aware there is a great danger now of further attacks," he said. "They will be desperate to find the people who did this and make sure they do not follow it up."

Roland Jacquard, a French terrorism specialist and a consultant to the United Nations said the attacks were a wake-up call for Europeans.

"We discovered today that this type of terrorism has arrived in Europe."