Police investigating radical Islamic cells in Spain arrested three Algerians and a Moroccan on Tuesday.

The four men were detained in the northern cities of Victoria and Teruel and in Madrid, said a national police spokesman, who spoke on condition of anonymity.

The Moroccan, Khalid Zeimi Pardo, 27, is suspected of ties to Moroccan fugitive Amer el Azizi, who is wanted in connection with the Madrid terror bombings and the Sept. 11 terror attacks in the United States, the spokesman said.

Zeimi Pardo also had contact with the alleged mastermind of the Madrid attacks, a Tunisian named Serhane Ben Abdelmajid Fakhet and others charged with terrorism in Spain, police say.

He was also detained in April but freed after five days due to insufficient evidence.

Authorities believe Azizi was a middleman between Spanish cells of mainly North African immigrants and Usama bin Laden's Al Qaeda (search) terror network.

Seventeen people, mostly Moroccans, are jailed in Spain on provisional charges over the Madrid train bombings (search), which are blamed on Islamist militants with possible links to Al Qaeda. The bombings killed 191 people and injured more than 1,800.

The arrests of the three Algerians, identified as Abdelkader Lebik, Abdallah Ibn Moutalib Kaddouri and Brahim Amman, are part of a police investigation into an Islamic cell that allegedly plotted to blow up the court overseeing Spain's anti-terror investigations, the spokesman said.

Thirty-three people, Moroccans and Algerians, have been provisionally charged and jailed since late October in the alleged plot to slam a truck carrying 1,100 pounds of explosives into Madrid's National Court.