German police have arrested three people near the western city of Aachen in connection with the Paris terror attacks.
The three were arrested in the town of Alsdorf, just north-east of the city, German news agency dpa reported.
Islamic State has claimed responsibility for Friday’s co-ordinated attacks, which killed at least 129 people.
France has made an unprecedented demand for its EU allies to support its military action against Islamic State, days after attacks in Paris killed at least 129 people.
The move came as the country launched new air strikes on the militants’ stronghold in Syria.
France invoked a never-before-used article of the EU’s Lisbon Treaty obliging members of the 28-nation bloc to give “aid and assistance by all the means in their power” to a member country that is “the victim of armed aggression on its territory”.
French defence minister Jean-Yves Le Drian said EU partners could help “either by taking part in France’s operations in Syria or Iraq, or by easing the load or providing support for France in other operations”.
The latest air strikes in Islamic State’s de-facto capital of Raqqa destroyed a command post and training camp, a French military spokesman said.
On Monday, President Francois Hollande vowed to forge a united coalition capable of defeating the jihadists at home and abroad.
The Paris attacks on Friday, claimed by IS, have galvanised international determination to confront the militants.
Mr Hollande has said the victims came from at least 19 nations, and the international community, led by the US and Russia, must overcome their deep-seated divisions over Syria to destroy IS on its home turf.
US Secretary of State John Kerry flew to France as a gesture of solidarity and met Mr Hollande and Foreign Minister Laurent Fabius on Tuesday.
Standing with Mr Hollande at the Elysee Palace, Mr Kerry said the carnage in the French capital on Friday, along with recent attacks in Egypt, Lebanon and Turkey, made it clear that more pressure must be brought to bear on the Islamic extremists.
Mr Kerry said: “We have to step up our efforts to hit them at the core where they’re planning these things and also obviously to do more on borders in terms the movement of people.”
Earlier, he told US Embassy staff that Friday’s attacks were an assault on civilisation and common decency.
“This is just raw terror,” he said, vowing that the campaign against IS will succeed. “We will end the scourge of Daesh,” he added, referring to the group by its Arabic acronym.
Addressing members of both houses of parliament on Monday after France observed a minute’s silence to honour the dead and the 350 wounded, Mr Hollande said “Friday’s acts of war were decided and planned in Syria”.
He added: “They were organised in Belgium and perpetrated on our soil with French complicity with one specific goal: to sow fear and to divide us.”
Mr Hollande said Syria has become “the biggest factory of terrorism the world has ever known and the international community is still too divided and too incoherent”.
French and other Western intelligence agencies face an urgent challenge to track down the surviving members of the three Islamic State units who inflicted the unprecedented bloodshed in France and, perhaps more importantly, to target their distant commanders in IS-controlled parts of Syria.
A French security official said anti-terror intelligence officials had identified Abdelhamid Abaaoud, a Belgian of Moroccan descent, as chief architect of the attacks on a rock concert, a football game and popular nightspots in one of Paris’ trendiest districts.
The official cited chatter from IS figures that Abaaoud had recommended a concert as an ideal target for inflicting maximum casualties, as well as electronic communications between Abaaoud and one of the Paris attackers who blew himself up.
Abaaoud came to public attention last year by boasting in an IS propaganda video about his pride in piling the dead bodies of “infidel” enemies into a trailer.
Anti-terror agencies previously linked him to a series of abortive shooting plots this year in Belgium and France, including a planned attack on a passenger train that was thwarted by American passengers who overpowered the lone gunman.
French police have used emergency powers to conduct almost 300 searches since Sunday night that netted 127 arrests and 31 weapons.
Interior Minister Bernard Cazeneuve said on Tuesday that police carried out 128 police raids overnight, as he conceded that “the majority of those who were involved in this attack were unknown to our services”.
Police have seized a Kalashnikov assault rifle, three automatic pistols and a bulletproof vest from a suspected arms dealer with jihadist sympathies, and a rocket launcher and other military-grade gear from his parents’ home.
But police have yet to announce the capture of anyone suspected of direct involvement in Friday’s attacks.
Seven attackers died – six after detonating suicide belts and a seventh from police gunfire – but Iraqi intelligence officials told The Associated Press that its sources indicated 19 participated in the attack and five others provided hands-on logistical support.