Police have detained a prayer leader at a suburban Paris mosque and 16 associates as part of an investigation into alleged terror financing, a police official said Tuesday.

Dahou Meskine, imam at the mosque in the suburb of Clichy-sous-Bois, and the 16 others were apprehended in separate raids around the capital early Monday, the official said.

Prosecutors believe the suspects were involved in a money-laundering scheme to benefit radical Islamic groups, the official said on condition of because the case is ongoing.

CountryWatch: France

The suspects remained in police custody and were being questioned by investigators. Under anti-terrorism laws, they can be held for up to six days for questioning.

The arrests were part of a probe launched 18 months ago based on information from Tracfin, an agency within the Finance Ministry that tracks money laundering, judicial officials said.

French intelligence officials say terror cells here have been changing their financing and planning methods, with funds often coming through inventive, small-scale sources such as halal butcher shops, trade in cannabis and ATM scams.

Many say the number of terror operatives in France, though impossible to pin down, is mounting, and warn that France could be in line for a terrorist attack. France stepped up anti-terrorist activities after a string of bombings by Algerian extremists in the 1990s, and has seen no major attacks since.

Meskine is a member of the Council of Imams of France, the judicial officials said, and is reported to be a founder of France's first Muslim middle school. The school could not be reached for comment Tuesday.