A Spanish judge has filed terror charges against 17 people for their alleged role in a suspected plot to blow up the National Court, a hub for the nation's investigations into Islamic terrorism.

Judge Baltasar Garzon filed the charges late Saturday after quizzing 18 suspects between Friday and Saturday. Eight of the suspects were arrested this week in connection with the alleged plot while 10 were already in jail for separate cases.

One of those arrested during the week, Smail Latrech of Algeria (search), was kept in custody pending further investigations.

Sixteen of the suspects, mostly Moroccans and Algerians, were charged with belonging to an armed group. The 17th, a Spaniard identified as Baldomero Lara, was charged with collaboration. No one was allowed bail.

The charges are temporary, pending further investigations, and do not constitute a formal indictment.

Garzon said the suspects formed part of a cell named the "Martyrs for Morocco (search)" that was set up by a man called Mohamed Achraf, 31, during his time in jail in Spain in 1999-2002 for credit card fraud.

Achraf was detained in Switzerland this week following a warrant by Garzon.

The cell's main plan was to detonate a truck packed with explosives at the court, Garzon said.

"Achraf had made the necessary preparations to acquire 1,000 kilograms (2,200 pounds) of explosives, of which at least 500 kilograms were to be packed into a truck that would be crashed into the National Court," Garzon said in his court order.

Achraf is believed to be Algerian and to have had ties to the Armed Islamic Group, which launched a violent campaign in 1992 to topple the Algerian government and set up an Islamic state.

Spain has asked for his extradition.

Garzon said Achraf ordered the attack to be carried out urgently and that the cost did not matter.

The group, he said, aimed "to end the lives of those inside (judges, officials and the public in general) and destroy archives which concern 'mujahedeen brothers."

He said one of the 10 already in jail, a Mauritanian named Kamara Birahima Diadie, was to make contact with a gypsy identified only as Antonio, who was to obtain the explosives. A Palestinian, identified only as Salim, was to prepare the mechanism to explode the bomb, the judge added.

Four persons, including Achraf, were to carry out the court attack, the magistrate said.

Garzon, an anti-terrorism specialist, works out of the court, which is located in downtown Madrid.

Achraf's name surfaced after police, acting on testimony from a protected witness in contact with Achraf this summer in Spain, arrested the eight purported cell members.

Garzon said three of those already in jail for membership in the Armed Islamic Group — Abdelkrim Bensmail, Mohamed Amine Akli y Bachir Belhakem — were also close friends of Allekema Lamari, one of seven militants believed to have been behind the March 11 train bombings in Madrid. The seven blew themselves up weeks later as police moved in to arrest them.

Achraf was arrested Aug. 28 for entering Switzerland without identifying documents. He was held in a detention center for illegal immigrants in Zurich and was awaiting deportation when officials learned he was allegedly linked to the Spanish plot.

Spanish police are believed to have intercepted calls made by Achraf and found mailed instructions from him.

In the court order, Garzon also issued arrest warrants for seven others.

Garzon has indicted 41 people over the past year on terrorism charges, including Osama bin Laden and other al-Qaida suspects accused of staging the Sept. 11 attacks in the United States.

Another judge, Juan del Olmo, is leading the probe into the March 11 bombings.