Diplomats from around the world pledged to fight ISIS militants "by any means necessary" as Iraq asked allies to thwart the extremists wherever they find sanctuary. Iran and the United States ruled out co-ordinating with each other, leaving Baghdad's government caught between two powerful and antagonistic allies.

Neither Iran nor Syria, which together share most of Iraq's borders, was invited to the international conference in Paris, which opened as a pair of French reconnaissance jets took off over Iraqi skies. But the U.S. State Department left open the possibility of new discussions with Iran later in the week, while precluding any military co-operation.

"We are asking for airborne operations to be continued regularly against terrorist sites. We must not allow them to set up sanctuaries. We must pursue them wherever they are. We must cut off their financing. We must bring them to justice and we must stop the fighters in neighbouring countries from joining them," President Fouad Massoum said.

With memories of the 2003 U.S. invasion of Iraq still raw, the U.S. has so far been alone in carrying out airstrikes and no country has offered ground troops, but Iraq on Monday won a declaration by the conference's 24 participant nations to help fight the militants "by any means necessary, including military assistance." An American official said Sunday several Arab countries had offered to conduct airstrikes, speaking on condition of anonymity to discuss the sensitive issue, and there were no public commitments on Monday.

"The threat is global and the response must be global," French President François Hollande said, opening the diplomatic conference intended to come up with an international strategy against the group. "There is no time to lose."

The killing of David Haines, a British aid worker held hostage by the militants, added urgency to the calls for a coherent strategy against the brutal and well-organized Sunni group, which is a magnet for Muslim extremists from all over the world.

The group, also known as Islamic State or ISIL, rakes in more than $3 million US a day from oil smuggling, human trafficking, theft and extortion, according to U.S. intelligence officials and private experts.

Massoum called for a co-ordinated military and humanitarian approach, as well as regular strikes against territory in the hands of the extremists and the elimination of their funding.

Harper calls ISIS 'evil'

Foreign Affairs Minister John Baird, Canada's representative at the conference, said all countries attending the conference have likely supplied foreign fighters to ISIS.


Iraq's President Fouad Massoum talks with Saudi Arabian Foreign Minister Prince Saud al-Faisal and Iraqi Foreign Minister Ibrahim al-Jaafari during the meeting in Paris. Muslim-majority countries are seen as key in the battle against ISIS. (Michel Euler/Reuters)

He said more needs to be done to stop the flow of foreign fighters into the Middle East conflict, and said Canada will be conducting military airlifts out of the Czech Republic to supply Kurdish fighters in northern Iraq with arms and ammunition.

Back in Canada, Prime Minister Stephen Harper called ISIS "evil" and "vile" in a speech to party faithful on the first day of Parliament after the summer recess.

"Canadians are rightly sickened by ISIL's savage slaughter of anyone who doesn't share their twisted view of the world,' Harper told Conservative supporters. "We know their ideology is not the result of 'social exclusion' or other so-called root causes. It is evil, vile, and must be unambiguously opposed."

Harper's veiled reference to Liberal Leader Justin Trudeau, who spoke about terrorism's "root causes" in the wake of last year's Boston Marathon bombing, was met by a ripple of laughter.

Kerry reinforces support for Iraqi government

After the Paris conference ended Monday, U.S. Secretary of State John Kerry met privately with Massoum at the Iraqi Embassy in Paris, telling him that the drive for an inclusive Iraq government had been key to Monday's pledges.

"So, I hope you feel that the push and the risk was worth it," Kerry said.

"We are beginning to feel it," Massoum said through a translator.

Fighters with ISIS, including many Iraqis, swept in from Syria and overwhelmed the Iraqi military in the Sunni-dominated Anbar province, capitalizing on long-standing grievances against the Shia-led government in Baghdad.

When the militants arrived in Mosul, Iraq's second-largest city, the U.S.-trained military crumbled and the militants seized tanks, missile launchers and ammunition, steamrolling across northern Iraq. The CIA estimates the Sunni militant group has access to between 20,000 and 31,000 fighters in Iraq and Syria.

Muslim-majority countries considered vital

Muslim-majority countries are considered vital to any operation to prevent the militants from gaining more territory in Iraq and Syria. Western officials have made clear they consider Syrian President Bashar al-Assad part of the problem, and U.S. officials opposed France's attempt to invite Iran, a Shia nation, to the conference in Paris.


French President François Hollande, right, called for a global response to ISIS, saying the group posed a security threat the world over. (Brendan Smialowski/Reuters)

Iranian Supreme leader Ayatollah Ali Khamenei, speaking on Iranian state television, said his government privately refused American requests for co-operation against the Islamic State group, warning that another U.S. incursion would result "in the same problems they faced in Iraq in the past 10 years."

U.S. State Department spokeswoman Jen Psaki declined to comment on specifics of any U.S. approaches to Iran, but said "we are not and will not co-ordinate militarily." Psaki said it was possible that U.S. and Iranian officials would be able to touch on the problem of Islamic State militants later in the week in New York.

Russian Foreign Minister Sergei Lavrov insisted Monday that Syria and Iran are "natural allies" in the fight against the extremists, and therefore must be engaged, according to Russian news agencies.

"The extremists are trying to use any disagreements in our positions to tear apart the united front of states acting against them," he said.

Iraq's president, who has said he regretted Iran's absence, appeared ambivalent about Arab participation, saying his country needed the support of its neighbours — but not necessarily their fighter jets or soldiers.

With files from The Candian Press