French President Francois Hollande (left) speaks with British Prime Minister David Cameron following talks on Monday at the Elysee Presidential Palace in Paris. Hollande said France would intensify its strikes against the Islamic State group in Syria. Photo: AFP

French President Francois Hollande received strong backing from British Prime Minister David Cameron on Monday as global efforts to crush the Islamic State (IS) gathered speed in the wake of the Paris attacks.

Speaking before scheduled meetings with the US, Russian and German leaders in the coming days, Hollande said Britain and France had a "joint obligation" to strike at the jihadist group.

"I firmly support the action President Hollande has taken to strike ISIL in Syria," Cameron said after talks in Paris, using another acronym for the IS. Cameron has said that he will make his case to the British parliament in the coming days about joining airstrikes on Syria.

While Britain has joined US-led coalition strikes on the IS in Iraq, it has so far held back from hitting targets in Syria, where the jihadists also hold large swaths of territory.

The British leader also said he had offered France the use of a strategically located British airbase in Cyprus, RAF Akrotiri, to facilitate airstrikes, and assist with refueling French jets.

Eye on Russia

Hollande, who has said France is in a "war" against the jihadists, is embarking on what could be a defining week of his three-year-old presidency.

On Tuesday, he will fly to Washington for talks with President Barack Obama and a day later will meet German Chancellor Angela Merkel in Paris.

The focus switches to Moscow on Thursday where he will meet President Vladimir Putin, who has pledged to work more closely with the West against the IS following the Paris attacks and the downing of a Russian passenger jet over Egypt last month. 

Completing a series of meetings with each of France's fellow UN Security Council members, Hollande will see Chinese President Xi Jinping for a working dinner in the French capital on Sunday, AFP reported. China has not officially announced Xi's meeting with Hollande. But Xi voiced his support for the Paris climate change summit when Hollande visited China earlier this month.

The Security Council on Friday authorized countries to "take all necessary measures" to fight the IS in a resolution that won unanimous backing in the wake of the bloodshed in Paris.

The measure drafted by France calls on all UN member states to "redouble and coordinate their efforts to prevent and suppress terrorist attacks" committed by the IS and other extremist groups linked to Al-Qaeda.

The French aircraft carrier Charles de Gaulle was steaming to the eastern Mediterranean on Monday to increase France's ability to fly bombing sorties over Syria.

US Secretary of State John Kerry has arrived in Abu Dhabi to speak to his Emirati counterparts on efforts to build a Syrian opposition coalition to lead peace talks with the Damascus regime.

Moscow on Monday said its warplanes had hit 472 targets in war-torn Syria in the past two days, including tanker trucks and oil infrastructure in territory controlled by the IS group.

Elusive fugitive

Belgian police on Sunday carried out 19 raids in Brussels and three in the industrial town of Charleroi, detaining 16 people but failing to find key Paris attacks suspect Salah Abdeslam, prosecutors said.

"Salah Abdeslam was not caught during the raids," federal prosecutor spokesman Eric Van Der Sypt told reporters just after midnight, meaning Europe's most wanted man remains at large.

Abdeslam's elder brother Brahim blew himself up outside a Paris bar in the November 13 attacks and the 26-year-old is suspected of playing a key role in the massacre.

Belgian capital Brussels was locked down for a third day under maximum terror alert Monday, with schools and the metro closed after police raids failed to track down key Paris attacks suspect Salah Abdeslam.

Prime Minister Charles Michel said Brussels, a diplomatic and business hub home to the European Union and NATO, faced a "serious and imminent" threat of attacks similar to those claimed by IS jihadists which left 130 people dead across Paris.

Germany has kept security along its border with Belgium at a high level since the Paris attacks, a German police spokesman said after media reports that Abdeslam was spotted near the frontier.

Several Belgian media carried unsourced reports saying he had been seen in a car near the eastern city of Liege heading toward Germany. There have been numerous reported sightings in recent days.

"Intensive border security measures have been in place since last week," the German police spokesman told Reuters.