European Law Enforcement Pursues Suspected Terrorists

An estimated 40,000 to 50,000 passengers were stranded for a few hours as police searched two regional railway lines. The officers were working on a tip from a Spanish CIA officer, who spoke of a possible attack on the lines Thursday evening, according to French police.

The threat comes in a week where counter-terrorism law enforcement across Europe have been launching pre-emptive strikes at suspected Islamic Jihadist cells. On Monday, France rounded up 13 suspected members of the Moroccan Islamic Combatant Group.

The group is blamed for coordinated bombings in Casablanca, Morocco last spring and is part of the focus of the investigation into the Madrid train bombings that killed 191 on March 11. Among those arrested, is the alleged leader, Mustapha Baouchi. French investigators said Baouchi was trained in explosives and weapons in Afghanistan, but that the arrests weren't related to the Madrid attacks.

Holy week tension

In Spain, 17 people have so far been charged in relation to the attacks. Holy Week in the Catholic country is taking place under heightened security measures and many are on edge after a message threatening to turn the country into an "inferno" was sent by Islamic fundamentalists to a newspaper and police revealed that the March 11 attackers were also planning an attack on a shopping mall.

Spanish police re-arrested a Moroccan man for the third time since the attacks on Thursday, bringing the total number of people in custody to 18.

British police officers conducted pre-emptive raids similar to those in France after March 11, rounding up nine men in London and the southeastern part of the country. The massive raids, in which 700 police officers were involed, netted half a ton of ammonium nitrate, a fertilizer that can also be used to make bomnbs. One of the suspects, a 17-year-old, has been charged with conspiring to set explosives.