The last three French detainees held at the U.S. military base in Guantanamo Bay (search), Cuba, returned to France on Monday and were detained by authorities, judicial officials said.

The detainees — Mustaq Ali Patel, Ridouane Khalid and Khaled Ben Mustafa — were being held by the French counterterrorism agency known as DST (search), the officials said on condition of anonymity.

The U.S. Department of Defense confirmed the transfer but declined to give details, citing operational and security considerations.

The three men were among seven French citizens captured in the U.S.-led campaign that toppled Afghanistan's hard-line Taliban (search) regime in late 2001. They spent more than two years at Guantanamo.

The four others — Mourad Benchellali, Imad Kanouni, Nizar Sassi and Brahim Yadel — returned to France in late July and are being held as part of an investigation into suspected terror networks.

French authorities said last month that details were being finalized with American officials about an eventual release of the three remaining detainees.

Foreign Ministry spokesman Herve Ladsous said the three men had been expected Monday evening, but did not elaborate. Defense lawyer William Bourdon said they were landing at Villacoublay military airport, south of Paris, but he could not confirm their arrival.

The Department of Defense said the handover raised to 211 the number of detainees who have been released from Guantanamo, including 146 who were released and 62 who were transferred to the control of other governments.

It did not specify the reason for the transfer of the three men, but said factors could include "whether the detainee is of further intelligence value to the United States and whether the detainee is believed to pose a continuing threat to the United States if released."

Some 540 prisoners are being held at Guantanamo Bay, according to the Defense Department, many without charge or access to attorneys.

Defense lawyers said the three were likely to go before an investigating judge. They could be held pending investigation under the preliminary charge of "criminal association with a terrorist enterprise" — a charge often used in such cases in France.

Renowned French anti-terrorism magistrate Jean-Louis Bruguiere opened a legal file on the cases in November 2002, after the French nationals were found to be in U.S. custody at Guantanamo.

Khalid's brothers, Djamel and Zinedine, already are being investigated in France on suspicion of involvement in the robbery of more than $1 million to finance terrorism. Zinedine Khalid also is being investigated separately in a case of suspected Chechen terrorism.

Judicial officials said Patel's case could present problems, because he does not appear to have links with Islamic militants and was thought to have been in the Pakistan-Afghanistan region for business reasons when he was detained.

"As for Mr. Patel, from what I know, we're looking at a series of bad coincidences and slightly disastrous random events," Bourdon said last month. "He was in Afghanistan long before the Taliban" controlled the country, he said.

Cousins of the Indian-born former imam say Patel, 45, was a victim of bad luck and bad timing who had settled in Afghanistan in the early to mid-1990s — long before the U.S.-led invasion of the country.