Led by US general John Allen, who had earlier commanded the 150,000 US and Nato forces in Afghanistan, the coalition meeting in Brussels is being billed as a co-ordination event.

"It’s made up of many diverse actors, all seized with the reality of degrading and defeating ISIL [Islamic State of Iraq and the Levant] as a global challenge," Allen said in Washington in mid-October.

The coalition includes all 28 members of Nato.

Nato itself is not part of it, but may in the future provide administrative co-ordination or intervene on training and humanitarian missions.

Some Arab states have also signed up, but have chosen not to go public in fear of generating domestic dissent.

It is unclear who exactly will show up at the Brussels event, given the tight security and secrecy surrounding the meeting.

But the coalition's priorities have been broadly outlined to include five strategic points.

The first is military.

Four new training camps to counter the militants will be set up in Iraq. The plan is to create 12 brigades, nine Iraqi and four from the Kurdish militia, the Peshmerga .

Supported by the coalition from the air, the 12 brigades will be Iraqi-led and possibly deployed into action sometime next spring for up to one year.

US forces are also training tribal fighters from Iraq’s Anbar Province, an area largely overrun by IS.

The second priority is dealing with foreign fighters.

An estimated 10,000 foreign fighters from around the world are now inside IS, although some are considered “jihadi tourists” - a term for visitors who do not take up arms.

Estimates of the number of Europeans are in the low thousands.

The third priority is to disrupt IS' revenue stream.

The militants are drawing large sums of money from oil, kidnapping, looting, checkpoint shakedowns, and selling off Syrian antiquities to wealthy bidders.

Coalition forces have already been dropping bombs on modular refineries and oil heads but want to track the money flows in the international financial system.

To date, some 900 bombs have been dropped on IS positions.

A lot of the IS money is going through banks in places like Qatar and Kuwait. Both countries have vowed to crack down on the illicit flows.

The fourth area is humanitarian assistance led primarily by the United Nations.

Concerns are mounting that counter-offensives to push out the militants will leave behind traumatised local populations in need of help.

The initial hours of the IS assault at Kobani, the Syrian border town, saw some 200,000 people flee into Turkey.

The fifth priority involves efforts to delegitimise the jihadist militants by targeting its value system and visibility.

The battle is likely to take years in war-torn Syria, while Western forces are hoping more concerted efforts in Iraq could see some form of resolution taking place within the next year to 18 months.

Jihadist recruitment drives in the EU are also putting pressure on European lawmakers to pass disputed legislation to create a broad legal basis for member state authorities to share things like airline passenger details.

A similar agreement with Canada has met tough resistance from the Greens in the European Parliament who want it scrutinised by the Luxembourg-based European Court Justice.

“While the exchange of passenger data may create a false sense of security, it is neither necessary nor effective in fighting terrorism,” said German Green MEP Jan Phillip Albrecht in a statement on Thursday (20 November).

Other member states like France and the UK want to confiscate passports of would-be fighters.