Counter-intelligence agents detained three suspects Monday in their investigation into a plot to attack the U.S. Embassy in Paris, police officials said.

Agents moved in on the three on orders from Investigating Magistrate Jean-Louis Bruguiere, who heads the probe into the plot by alleged Islamic radicals.

Former Tunisian soccer player Nizar Trabelsi, alleged to have been set to be the suicide bomber in the plot, is under arrest in Belgium. Four other men were tried earlier this month in the Netherlands, accused of providing stolen passports and credit cards as part of the plan to attack the U.S. Embassy in Paris and a military depot in Belgium. The verdict was expected Dec. 18.

The latest three to be detained were suspected of possible logistical support in the plot, according to the police officials who did not elaborate. The men, who were not identified and whose nationalities were not released, were detained before dawn at their homes south of Paris, in Grigny and Corbeil-Essonnes, the officials said.

They can be held for up to four days while investigators decide whether to release them or place them under formal investigation.

Djamel Beghal, an alleged ringleader in the plot, had lived in the working class suburb of Corbeil-Essonnes, where the three were picked up, before moving to Britain. Another suspect, Kamel Daoudi, took over Beghal's apartment. Both men are jailed.