France is at immediate risk of a major terror attack by Islamist radicals and has reinforced urgent security measures introduced last week, officials say.

France is at immediate risk of a major terror attack by Islamist radicals and has reinforced urgent security measures introduced last week, officials say.

Asked about reports that an attack might be imminent, French Interior Minister Brice Hortefeux said on Monday that the threat was real and that “we have stepped up our vigilance”.

Separately, a source close to the Interior Ministry confirmed that police were investigating reports that a female suicide bomber might be preparing a strike in Paris, but added: “That’s not necessarily the most worrying thing.”

Instead, the source explained, Paris was concerned with intelligence received from an allied foreign spy agency that al-Qaeda’s North African branch, al-Qaeda in the Islamic Maghreb (AQIM), was planning an “imminent” attack in France.

“It’s a threat which we think might target transportation,” he said, speaking on condition of anonymity and without giving further details except that the warning was received on Thursday last week.

The Interior Ministry played down the specific risk to transport, insisting that the threat was “against totally undefined targets”.

Meanwhile, according to a police source, authorities have learned that two dormant Islamist networks in France have been revived to receive and host groups of jihadi radicals returning from Pakistan and Afghanistan.

Separately, officials from Paris’s Grand Mosque confirmed that their rector, Dalil Boubakeur, had been placed under police protection and provided with an escort as he moves about the city.

Boubakeur is a moderate figure who has worked with France’s government on issues of Muslim integration and has been threatened by radicals.

Last Tuesday, hundreds of tourists were moved away from the Eiffel Tower as it was briefly evacuated following a hoax bomb threat.

France’s national terror warning plan, known as “Vigipirate”, was already at alert level “reinforced red” – one step down from the highest level, scarlet, which would represent a precise and imminent threat.

The warnings were the latest in a series given over the past 10 days since the head of France’s DCRI domestic intelligence agency, Bernard Squarcini, said France had never faced a greater “terrorist threat”.

They come at a time when France has been the target of violent threats on jihadi websites, including from known armed militant leaders, over its ban on the full-face Muslim veil and its overseas military operations.

Senators voted last week to pass the ban on the burqa and the niqab, and it will go into effect within six months if approved by constitutional judges.

Before the law was voted on, al-Qaeda’s Egyptian number two, Ayman al-Zawahiri, released an audio tape urging Muslim women to resist the ban.

French troops, meanwhile, are fighting Islamic militants in both Afghanistan – where they are part of the NATO mission – and northwest Africa, where in July they took part in a commando raid against an AQIM base.

The July 22 strike, carried out alongside Mauritanian troops operating in northern Mali, left seven militants dead but failed to find a French hostage, 78-year-old aid worker Michel Germaneau, who is thought to be dead.