BARCELONA - As the terrorism suspects congregated in the largely Pakistani neighborhood here over the past few months, they were joined by a young man who called himself Asim. He had come from the Pakistani borderlands where Al Qaeda's leadership is said to have regrouped.
The suspects, he later told Spanish investigators, envisioned a wave of spectacular attacks: Coordinated suicide bombings would start in Barcelona's vast subway system and then sweep through Portugal, Germany, France, and Britain if certain demands were not met.
Asim had been sent to Spain to be a suicide bomber, but he also was an informer for French intelligence working in the no man's land of Waziristan in Pakistan.
After he got word to his handlers of an impending attack, Spain's military police swooped into the neighborhood of Raval in the early hours of Jan. 19 and arrested 14 men.
Now the officials unraveling the case say it reveals the growing threat of terrorist activities migrating to mainland Europe from Pakistan.
The largely Pakistani cell formed quickly in Barcelona with support, and perhaps direction, from the tribal areas of Pakistan, the authorities said.
According to the arrest warrant in the case, three suicide bombing suspects arrived in Spain within the last four months, and the bomb-making suspect had recently spent five months in Pakistan.
With Spain preparing for elections in March, the suspected plot was an eerie echo of the March 11, 2004, Madrid transit bombings, which killed 191 people just days before the country's last election.
In the weeks since the arrests, Spanish officials have backed off their claim that an attack was imminent. They seized evidence such as broken timing devices and small quantities of explosives. But they acknowledged that without more evidence of bomb making, they were relying heavily on the testimony of the informer to make their case, which had blown the cover of a rare intelligence source with access to Pakistan's tribal areas.
Even so, in interviews, US, Spanish, and other European officials - most speaking on condition of anonymity because the inquiry is not over - called the plot serious and indicative of the terrorist threat from Pakistan.
"That these people were ready to go into action as terrorists in Spain - that came as a surprise," said Judge Baltasar Garzon, Spain's highest antiterrorism magistrate. "In my opinion, the jihadi threat from Pakistan is the biggest emerging threat we are facing in Europe. Pakistan is an ideological and training hotbed for jihadists, and they are being exported here."
Officials say the Barcelona case points to a more serious dynamic: Pakistanis with no apparent previous links to Europe who appear to have been sent there on a terrorist mission.
"We had 20 terrorists show up in Spain that had been trained in Pakistan that were going to be suicide bombers, fanning out over Europe," Mike McConnell, director of US national intelligence, told the House Intelligence Committee on Thursday.
Although some of the suspects had been living in Spain, McConnell's remarks underscored statements by the Spanish authorities that in addition to the 14 suspects who had been arrested, others had eluded capture.
In late 2004, the police arrested 11 Pakistani men on suspicion of plotting to attack two landmark buildings in Barcelona, financing terrorism, and drug trafficking, although only six were convicted, two for document forgery.
