AFP/ Paris

The UN Security Council Friday urged its members to ramp up their fight against Islamic State jihadists after the Paris attacks, as Europe said it would tighten border checks and Brussels issued its highest terror alert.

Hours before the UN Security Council passed the resolution authorising countries to "take all necessary measures" against IS, gunmen stormed a luxury hotel in Mali's capital, taking more than 100 people hostage in a siege that left at least 27 dead.

The attack on Bamako's luxury Radisson Blu hotel added to fears about the global jihadist threat a week after attacks in Paris left 130 people dead, although there was no immediate confirmation of a link with IS.

In the European Union, ministers agreed to rush through reforms to the passport-free Schengen zone to tighten the bloc's borders, and Belgium put out its highest terror alert in its capital, warning of a "serious and imminent threat".

Officials declined to add further details until later on Saturday "in order to allow ongoing judicial investigations to follow their course", the OCAM national crisis centre said in a statement.

The 28-year-old suspected ringleader of the Paris attacks, Abdelhamid Abaaoud, a Belgian of Moroccan origin, is believed to have travelled to Syria to join IS and be trained as an operative in Europe.

News that he and another attacker were able to slip back into Europe from Syria, despite being the subject of international arrest warrants, has raised fears jihadists are taking advantage of the migrant crisis to carry out attacks.

One of the suspected gunmen in the Paris attacks linked to Abaaoud, 26-year-old Brussels resident Salah Abdeslam, is still the subject of a huge international manhunt.

In Syria, meanwhile, a monitoring group said at least 36 people were killed in air strikes by Russian and Syrian jets in the IS-controlled eastern Deir Ezzor province, describing them as the heaviest in the region since the start of the civil war.

- Russia pounds Syria -

At the United Nations, Russia joined Western powers in backing the French-drafted text that authorises countries to "take all necessary measures" to fight IS and other extremist groups linked to Al-Qaeda.

Describing IS as a "global and unprecedented threat to international peace and security", the resolution called for sanctions and urges countries to step up efforts to cut off the flow of foreign fighters to Iraq and Syria.

French President Francois Hollande welcomed the move, even though the text does not provide any legal basis for military action, saying it will "contribute to mobilising nations to eliminate Daesh" (IS).

French diplomats argue it will provide important international political support to the anti-IS campaign, which has been ramped up since the attacks in Paris and after IS claimed it downed a Russian passenger jet in Egypt last month.

"Today's vote shows beyond doubt the breadth of international support for doing more in Syria and for decisive action to eradicate ISIL," said British Prime Minister David Cameron, using another term for IS, which he labelled an "evil death cult".

Russia pounded the jihadist group in Syria on Friday, firing cruise missiles from warships in the Caspian Sea into IS-controlled territory in what the defence ministry called an "aerial campaign of retribution" against the jihadists.

"At least 36 people were killed and dozens more injured in more than 70 raids carried out by Russian and Syrian planes against several districts in Deir Ezzor," Rami Abdel Rahman of the Syrian Observatory for Human Rights monitoring group told AFP.

He described the raids as "the worst bombardment of the region since the start of the uprising in 2011".

- EU tightens borders -

In Brussels, French Interior Minister Bernard Cazeneuve said he and his EU counterparts agreed in crisis talks to "immediately" tighten checks on points of entry to the 26-country Schengen area.

Cazeneuve said the European Commission would present plans to introduce "obligatory checks at all external borders for all travellers", including EU citizens, by the year's end.

Previously, only non-EU nationals had their details checked against a database for terrorism and crime when they enter the Schengen area.

Dutch Prime Minister Mark Rutte said late Friday he was increasingly irritated that the EU was moving so slowly to secure its borders, adding the Netherlands was ready "to run the whole show" with other countries if necessary.

Abaaoud, a Belgian national, was killed in a ferocious police onslaught Wednesday on an apartment building in the Saint-Denis suburb of Paris, where the attacks began on November 13 with three explosions outside the Stade de France stadium.

A police source on Friday said his cousin Hasna Aitboulahcen, who also died in the raid, had not blown herself up as initially thought, adding that the suicide bomber was instead thought to have been a second man.

The apartment block was severely damaged as police fired 5,000 rounds of ammunition and lobbed in grenades at it after a tip-off that Abaaoud was there.

Investigators revealed Friday that he was caught on camera at a metro station in the east of the capital on the night of the attacks, as the massacre at Bataclan concert hall was under way.