A global agency fighting terrorist financing says Islamic State extremists are financially vulnerable as oil prices have fallen and their ability to extort resources in Iraq and Syria is peaking.

The Paris-based Financial Action Task Force, in a report released Friday, urges governments to do more to starve the group of funds.

The report says most of Islamic State's money comes from looting banks and farms, selling oil, kidnapping for ransom, remittances from abroad, and donations.

It says airstrikes by the U.S.-led coalition and falling oil prices have "significantly diminished" the group's oil revenue recently. It urged governments to do more to fight the group's online crowd-funding and other fundraising.

The report's authors would not comment on suspected large donations from Gulf countries.