PARIS (AP) — A French judge decided on Tuesday to keep prominent Islamic scholar Tariq Ramadan in detention, four days after he was handed preliminary rape charges in cases alleged by women who sought his counsel.

A judicial official, who wasn't authorized to speak publicly about the cases, said the decision followed the recommendation of the prosecutor's office.

Ramadan was placed under investigation on Feb. 2 for an alleged rape resulting from a 2009 encounter and for the alleged rape of a vulnerable person in a 2012 case. Both women filed the complaints last year.

Ramadan, in custody since Jan. 31, denies any wrongdoing.

Ramadan had sought to buy some time before the judge ordered him kept in decision, saying last week after being charged that he wanted to postpone the required "debate" before any decision on remaining in jail. The tactic apparently didn't work.

Ramadan, 55, is on leave from Britain's Oxford University, where he is a professor of contemporary Islamic studies. He travels frequently and has written numerous books on Islam and the integration of Muslims in Europe.

It was not known how long he could remain locked up. Under French law, the order to hold him in "provisional detention" can last one year and include two consecutive six-month renewals thereafter. However, a suspect's time in custody can be cut short at any time if a judge agrees detention is no longer warranted.

He is being investigated by French authorities because the rapes are alleged to have taken place in Paris and Lyon.

The judicial official said that in ordering Ramadan to remain in jail, the judge was either weighing the well-being of the women behind the case or assuring that the scholar does not leave France while the investigation is in progress

The preliminary charges filed Friday can be dropped at the end of the probe, or turn into regular charges if the suspect is indicted and sent to trial.