Since the Paris attacks in November, some 50 countries have responded to a new call by the Paris-based Financial Action Task Force (FATF) for concrete steps to choke the funding of terrorist organisations, the body's executive secretary, David Lewis, told AFP.
The threat of inclusion on the FATF's black list of governments failing to comply has been instrumental to get this response, he said in an interview, as states tried to avoid being named and shamed.
"So we see countries act very quickly to ensure that they do not get onto that list."
The FATF's current black list includes North Korea, Afghanistan and Syria.
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Iran is also high on the list but Tehran, which last July signed a deal with western powers ending economic sanctions, has now signalled its willingness to cooperate, Lewis said.
"Iran is coming back to the table. They have approached us. They have shown a willingness to start cooperating with us," he said.
The FATF, created in 1989 to promote the fight against money laundering, terrorism financing and other threats to the international financial system, has found that governments' responses are still inadequate measured against the threats.
The use of tools at governments' disposal "is much lower than it should be given the threat we face", Lewis said.
"Only 36 countries have ever convicted someone for terrorism financing and only 40 have used targeted financial sanctions," he noted.
"In a world where you can move funds in seconds online, that is not an adequate response to the threat we are facing," he said, adding his organisation had made a push for swifter action a priority.
Targeting money flows exploits a major vulnerability of organisations like Islamic State who need massive funds to function, Lewis said.
"They require substantial amounts of money to be able to operate, because they try to provide some of the services of a state.