Paris attack prompts calls for greater security powers

Parker said some privacy rules need to be roll backed in order for the agency to properly conduct its operations, warning more attacks are “highly likely”, reports the Guardian newspaper.

“My sharpest concern as director general of MI5 is the growing gap between the increasingly challenging threat and the decreasing availability of capabilities to address it.”

For Nato Secretary General Jens Stoltenberg, it means stepping up investments in security and defence.

“We have to invest in security, to invest in defence. Because we have to strengthen our ability, and adapt to the new security environment,” he said in statement.

This includes tracking people who have left for Syria and Iraq to fight alongside ISIS.

Estimates put forward by the EU police agency Europol suggest up to 2,500 fighters are EU nationals. The fear is that some who return may carry out terror attacks on EU soil.

"In Italy, we have counted 53 foreign fighters," Italian interior minister Angelino Alfano told RAI public broadcaster on Thursday.

Alfano said this means police surveillance should be increased on the Internet where some potential jihadists are recruited.

Other national measures seek to prevent people from fighting along Islamist militants in Iraq and Syria by tracking their flight passenger details or confiscating their passports.

Meanwhile, the hunt for the Charlie Hebdo gunmen continues in the Picardy region of northern France. The two brothers were spotted on Thursday in the area after robbing a petrol station.

The French government has deployed some 88,000 police officers in the effort.

Twelve people died in Wednesday's gun attack, including a Muslim police officer Ahmed Merabet, who was shot in the head after attempting to stop the killers from fleeing the scene.

Mosques across France are set to condemn the violence on Friday.