A new foundation is planned to help finance the construction and administration of mosques in France, the head of the French Muslim Council has said, as the country's prime minister and dozens of prominent French Muslims have called for action to stop "radicalisation".

Anouar Kbibech said on Monday that the foundation would be financed by fees paid by actors in the halal food sector to keep out "radical" benefactors.

The announcement came a day after Prime Minister Manuel Valls said in a statement in the Journal du Dimanche newspaper that he wanted to put an end to the financing from abroad for the construction of mosques.

He called for a new "pact" with the Muslim community in France, which includes about five million members.

"There is an urgent need to help Islam in France to rid itself of those who are undermining it from the inside," he said. "To do that, we have a duty to build a real pact with Islam in France, and give the foundation a central role."

READ MORE: Muslims of France

Also on Sunday, 41 prominent Muslims, including former ministerial advisers, entrepreneurs, lawyers, scientists and academics, published a joint letter pledging: "We, French and Muslim, are ready to assume our responsibilities".

"We Muslims were silent before because we understand that in France religion is a private matter," they said, calling for "a cultural battle against radical Islamism among the youth".

The debate has been prompted by an attack on an elderly priest in a Normandy church last week by two Muslim men with alleged links to the Islamic State of Iraq and the Levant (ISIL, also known as ISIS).

The attack came as France was on high alert after an attack in Nice that killed 84 people and a string of deadly attacks last year claimed by ISIL.

France, home to Europe's largest Muslim community, is a secular state that prohibits the use of state money for the construction of places of worship.

Mosques shut down

The authorities have shut down about 20 mosques and prayer halls considered to be preaching "radical" Islam since December, Interior Minister Bernard Cazeneuve said on Monday.

"There is no place ... in France for those who call for and incite hatred in prayer halls or in mosques, and who don't respect certain republican principles, notably equality between men and women," Cazeneuve said.

"That is why I took the decision a few months ago to close mosques through the state of emergency, legal measures or administrative measures. About 20 mosques have been closed, and there will be others."

READ MORE: Is Europe under attack?

There are some 2,500 mosques and prayer halls in France, about 120 of which are considered to be preaching Salafism, a strict Sunni interpretation of Islam.

He said that since 2012, 80 people had been expelled from France, and dozens more expulsions were under way, without giving further details.

Cazeneuve was speaking after a meeting with leaders of the French Council of the Muslim Religion.

He confirmed that authorities were working on a French foundation for Islam which would guarantee total transparency in financing of mosques "with rigorous respect for secular principles".