WASHINGTON (AFP) - Members of a United States-led coalition fighting the Islamic State in Iraq and Syria (ISIS) militant group on Thursday vowed to stick by global resolutions to refuse to pay ransoms for citizens held hostage by militants, US officials said.

The pledge to abide by United Nations Security Council resolutions came after some 25 members of the coalition Counter-ISIL Finance Group met in Jeddah, Saudi Arabia on May 7. ISIL is another name for the ISIS militant group.

A communique issued by the group "rejects the payment or facilitation of ransoms to ISIL, so as to deny ISIL an important source of funds and remove a key incentive for ISIL to engage in further kidnapping or hostage-taking activities," the US Treasury and State Departments said.

The group, co-chaired by Italy, Saudi Arabia and the United States, was set up in Brussels in 2014 as part of US-led efforts to fight the militants.

It also urged "private sector partners to adopt or to follow relevant guidelines and best practices for preventing and responding to ISIL kidnappings without paying ransoms." American, Japanese and Jordanian hostages have been among those brutally killed by IS militants after being kidnapped during the group's march across swathes of Iraq and Syria.

While the US has staunchly stuck to its policy of refusing to pay money to win the release of its nationals, arguing that such a move would endanger all Americans, other Western countries are known to have paid large ransoms to free hostages.

The statement backed by 25 nations will give a boost to the US policy, even as the administration of President Barack Obama reviews the stand following sharp criticism, particularly from the hostages' families.

"We understand the policy about not paying ransom," Carl Mueller, father of American aid worker Kayla Mueller, 26, who died while after being kidnapped in the Syrian city of Aleppo, said in February.

"But on the other hand, any parents out there would understand that you would want anything and everything done to bring your child home. And we tried. And we asked. But they put policy in front of American citizens' lives." US officials have alleged that ISIS at one point was one of the world's richest terror groups, raising US$2 million a day from the illicit sales of crude from captured oil fields.

Since then the US-led coalition has targeted captured oil fields in air-strikes aiming to choke off finances to IS.

Ransoms and the sales of plundered cultural treasures were also lucrative money earners for the group which has to ensure vital services for residents in cities it has captured, like the Iraqi second hub of Mosul.

"The latest trends in ISIL's exploitation and smuggling of energy resources and cultural property" were also discussed by the working group, the State Department said.

They also discussed "concrete measures" to disrupt the flow of funds to the group.