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.

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.

The older brother of the Toulouse gunman who killed seven people said he was "proud" of Mohammed Merah's actions, police said Saturday.

Abdulkader Merah also admitted being present when the scooter used in the killings was stolen, even though he had said he knew nothing of his brother's criminal intentions.

French officials rejected charges that intelligence failures let a young man kill seven people, as the crack police unit that finally killed the gunman faced criticism of their operation.

Several security experts in Israel were scathing of the French police's handling of the siege, with one specialist calling it a disgrace.

France's prime minister on Friday rejected accusations his government could have prevented the multiple murders by an Islamic militant who was supposedly being watched by intelligence services.

Francois Fillon said security officials knew Mohammed Merah, who died in a hail of police bullets, was a radical Islamist who had visited Afghanistan but insisted there was no reason to suspect he was planning an atrocity.

Extremists must stop using the Palestinian cause to justify their acts of violence, Prime Minister Salam Fayyad said on Wednesday after a deadly attack on a French Jewish school.

"It is time for these criminals to stop marketing their terrorist acts in the name of Palestine and to stop pretending to stand up for the rights of Palestinian children who only ask for a decent life," the Palestinian premier said in a statement.

French police laid siege Wednesday to an apartment block where a self-declared al-Qaida militant who has claimed a series of deadly attacks on troops and a Jewish school was holed up.

Prosecutors said suspect Mohamed Merah, a 23-year-old Frenchman of Algerian descent, had fought off several police assaults on his flat and bragged to negotiators of having been trained by al-Qaida on the Afghanistan-Pakistan border.

The bodies of four Franco-Israeli citizens, three of them young children, who were murdered in a French school shooting, were to be flown to Israel on Tuesday, a Jewish community body said.

Teacher Jonathan Sandler, his two sons Gabriel, 4, and Arieh, 5, and a seven-year-old pupil at the Ozar Hatorah school, Myriam Monsonego, were to be brought to Paris from Toulouse before being put on a plane.

Israel's Foreign Minister Avigdor Lieberman on Tuesday condemned the EU's foreign policy chief for remarks she made drawing a parallel between Monday's Toulouse attack and the plight of children in Gaza.

"The minister felt that the declarations of Catherine Ashton were not appropriate and he expressed the hope that she would reexamine and reverse them," a statement from Lieberman's office said.

Chief Palestinian negotiator Saeb Erakat on Monday condemned an attack by an unidentified gunman who killed four people at a Jewish school in France, including an Israeli-French dual citizen.

"We strongly condemn all terrorist operations, and in particular the attack today in Toulouse," he said in an statement.