One of five suspected Islamist militants arrested in France earlier this week was "ready to die" for his cause, Interior Minister Brice Hortefeux said Wednesday.

All the suspects were French, some of Algerian origin and "clearly belong to the radical Islamist movement," the minister said.

"One of the five said they were ready to die for the cause," Hortefeux told journalists following the arrest of four men and a woman in Paris and at the city's main Charles de Gaulle airport on Monday and Tuesday.

"One of the five spent some time in Afghanistan," Hortefeux said. Earlier, an official source had claimed all five had trained in the Pakistani-Afghan border region, a known haven of Islamist extremists.

"At least one of them had been to Afghanistan and was unquestionably very familiar with jihadi Internet sites, while others were planning to go to Pakistan," he said.

"One of them was allegedly involved in a plan to murder the head of Paris' great mosque, Dalil Boubakeur, and this cell is today dismantled."

The alleged plot to kill Boubakeur is "taken all the more seriously because the wave of attacks that hit our country in 1995 began with the killing of imam Saraoui from the mosque on the rue Myrrha," in Paris, Hortefeux said.

A wave of bombings by militants seeking to bring the Algerian civil war to France in 1995 killed eight people and wounded more than 100.

Boubakeur has been under heightened police protection in recent months.

Al-Qaeda leader Osama bin Laden warned France in October that its planned ban on the Islamic full-face veil in public places and its involvement in the war in Afghanistan justified violence against its nationals.

Hortefeux subsequently said that France faced a real terror threat that will require "total vigilance."

On October 17, Hortefeux said that Saudi security forces had warned about an Al-Qaeda threat to Europe and to France in particular.

In September, he also mentioned two other threats -- one based on a warning from Interpol and another of a possible attack by a female suicide bomber.

Western security officials have also warned that Al-Qaeda may be planning attacks in Europe similar to those that struck Mumbai in 2008.

On Saturday, French police arrested a man in his thirties suspected of having travelled to the sensitive Pakistan-Afghanistan border region.

He has been held in custody pending trial on charges of "criminal association and relations with a terrorist enterprise."