Summit: President Obama will gather world leaders in Washington to discuss the rise of extremism

President Barack Obama will invite allies to a Feb. 18 security summit in Washington to try and prevent violent extremism, U.S. Attorney General Eric Holder said on Sunday after meeting his European counterparts in Paris.

The gathering of justice and interior chiefs came as France mourned 17 victims of Islamist gunmen this week in the worst assault on its homeland security in decades.

'We will bring together all of our allies to discuss ways in which we can counteract this violent extremism that exists around the world,' Holder told reporters.

French Interior Minister Bernard Cazeneuve said after the meeting that European interior ministers had agreed to boost cooperation in an effort to thwart further jihadist attacks.

'We all agree that we need to put in place better control on certain passengers, on the basis of objective criteria and with respect for fundamental liberties and without disrupting cross-border travel,' he said.

He said Europe needed urgent progress in establishing a European Passenger Name Record database, which would facilitate the exchange of data about passengers between member states.

'We are convinced of the need for such a tool, to follow those who travel to terrorist operating theatres or who return from there,' he said, adding that this database would also be useful in the fight against other serious crimes.

Cazeneuve said the Internet needs to remain a space for free expression, but that Europe should fight against abusive use of the web to spread hate speech, anti-Semitic messages and the recruiting vulnerable young people for violence.

'We need to work more closely with Internet companies to guarantee the reporting and if possible removal of all content that amounts to an apology of terrorism or calls for violence and hatred,' he said.

Cazeneuve said EU interior and justice ministers planned to meet soon to discuss further action. A European source said the meeting could take place next week in Brussels.

Holder said on Sunday he is concerned about so-called lone wolf attacks in the United States by Islamist militants inspired by al Qaeda affiliates.

Holder met with his European counterparts on Sunday. The gathering of justice and interior chiefs came as France mourned 17 victims of gunmen this week in the worst assault on its homeland security in decades

Greetings: Holder is seen with French Interior Minister Bernard Cazeneuve. Cazeneuve said after themeeting that European interior ministers had agreed to boostcooperation in an effort to thwart further jihadist attacks

Holder met with his European counterparts in Paris on Sunday to discuss ways to prevent violent extremism, after Islamist militants killed 17 people in several attacks in the French capital.

Holder said on CBS's 'Face the Nation' program that the 'decimation' of core al Qaeda has reduced or eliminated that group's ability to carry out a 9/11-style attack, but he said affiliates like al Qaeda in the Arabian Peninsula (AQAP) have stepped in to try to inspire people to carry out smaller attacks.

'I think the possibility of such attacks exists in the United States,' Holder said.

'It is something that, frankly, keeps me up at night worrying about the lone wolf or a very small group of people who decide to get arms on their own and do what we saw in France this week,' he said.

Holder said authorities have not determined if AQAP or a group like Islamic State, which has declared a caliphate and seized large areas of Iraq and Syria, is responsible for the Paris attacks.

The two brothers who carried out the attack in Paris on a satirical weekly newspaper traveled in 2011 to Yemen, where AQAP is based, for weapons training, two senior Yemeni sources said on Sunday. The gunman who staged an attack on a Paris deli appeared in a video declaring his allegiance to the Islamic State group.

Holder, who appeared on several U.S. television shows on Sunday morning, said the United States and its allies need to do a better job sharing information about possible threats.

'One nation cannot by itself hope to forestall the possibility of terrorism even within its own borders,' he told ABC's 'This Week' program.

President Barack Obama will hold a global security meeting in Washington in February to discuss domestic and international efforts to counteract violent extremism.

Holder said Americans should feel secure with U.S. officials' efforts to prevent attacks by Islamist militants.

He told CNN's 'State of the Union' program that about 150 Americans had gone or attempted to travel to Syria or Iraq to fight with militants there, and about 12 were there now.