France has advised its nationals "whose presence is not essential" to leave Mali as Tuareg rebels sweep across the north of the country in the wake of a military coup, the Agence France Presse said Monday.

"It is recommended not to travel to Mali until further notice," said a statement on the French foreign ministry's travel advice website after the rebels last week seized several towns in the north, including Timbuktu.

A deadline must be set for the Syrian regime to implement a peace plan by international envoy Kofi Annan, France's foreign minister said on Sunday.

"There is a risk of course of dragging out, and we can see the tactics of the regime that is to buy time," Alain Juppe told reporters on the sidelines of the second "Friends of Syria" conference in Istanbul.

The 17 people detained by French police in a crackdown on suspected Islamist networks were on Sunday remanded in custody for at least another 24 hours, a source close to the inquiry told AFP.

Friday's arrests were made in connection with a probe into an alleged terror plot and under French anti-terror laws the suspects can be held without charge until Tuesday.

French police swooped down on suspected Islamist networks Friday, arresting 19 people as President Nicolas Sarkozy vowed a crackdown would continue after an extremist gunman's killing spree.

The arrests took place in several cities including Toulouse, where Mohammed Merah was shot dead by police last week after a series of cold-blooded shootings in southwestern France that left seven dead.

France said Thursday it had banned four Muslim preachers from entering France to attend an Islamic conference, saying their "calls for hatred and violence" were a threat to public order.

President Nicolas Sarkozy had wanted to ban the high-profile Islamic clerics from attending the conference next month in the wake of a series of killings by al-Qaida inspired gunman Mohammed Merah that shocked France.

The Friends of Syria meeting in Istanbul Sunday will be a chance for the international community to judge if Bashar al-Assad's regime is implementing Kofi Annan's peace plan, France said.

"Bashar al-Assad has supposedly accepted Kofi Annan's peace plan," French foreign ministry spokesman Bernard Valero told a press conference on Wednesday.

The body of an Islamist gunman branded a "monster" who boasted of killing seven people in southern France is due to arrive in Algeria on Thursday, a family member told AFP on Wednesday.

Mohammed Merah, a 23-year-old Frenchman of Algerian descent, was killed by police March 22 after a lengthy stand-off at his Toulouse apartment.

An angry France won a pledge Tuesday from the Al-Jazeera news channel not to air a video shot by an Islamist extremist during a murderous shooting spree targeting soldiers and Jewish children.

President Nicolas Sarkozy demanded that the channel not broadcast the video sent to its Paris bureau, which includes graphic footage shot by Mohamed Merah during attacks this month in southern France that left seven people dead.

French Foreign Minister Alain Juppe said Tuesday that the father of an Islamist gunman who has threatened to sue over his son's death at the hands of police should keep silent in shame.

"If I were the father of such a monster, I would shut my mouth in shame," Juppe told Radio Classique.

The Toulouse gunman who killed seven people, including three young Jewish children, visited Israel for three days in 2010, Israeli security officials told Agence France Presse on Monday.

They said that Mohamed Merah entered the Jewish state on a French passport in September 2010 through the Allenby Bridge crossing from Jordan where he was checked and given a tourist visa.