Spanish police have arrested five more people in connection with the Madrid train bombings that killed 190 people, raising the total number of suspects in detention to 18, officials said yesterday.
An Interior Ministry spokesman said three people were arrested on Wednesday and two more yesterday.
But he could not comment on German media reports that at least one of them had lived in Darmstadt - which could be significant as the September 11, 2001 attacks on US cities were believed to have been planned in Spain and Germany.
In the United States, CIA Director George Tenet said intelligence "strongly" suggested locally based extremists linked to al Qaeda were responsible for the March 11 bombings in Spain, but there was no information that the leadership of Osama bin Laden's network ordered the attack.
Sources close to the Spanish investigation had said the masterminds of the plot were most likely still at large.
Eighteen people are now in custody as part of the probe into the deadliest bombing attack in Europe in 15 years. The bombings also helped tilt March 14 general elections to the opposition Socialist party.
At least 13 of the suspects being held are from Morocco and investigators believe the attacks were carried out by Islamic radicals linked to al Qaeda.
In addition to the 190 deaths, about 1,900 people were wounded when 10 bombs exploded at roughly the same time on four packed commuter trains on the morning of March 11.
A man claiming to be a spokesman for al Qaeda in Europe claimed responsibility for the attacks in a videotape that surfaced on election eve and said the blasts were retaliation in part for Spanish support for the US-led war in Iraq.
Spain's role in Iraq was already an unpopular policy at home and voters handed the ruling party a shock defeat in the elections held just three days after the attack.
Investigators believe at least two of those held placed the bombs on the trains but that most of the others behind bars played lesser roles.
One Spaniard is in detention on suspicion he helped the plotters steal the dynamite used to make the bombs.