The Islamic State group’s finance chief was killed in a coalition air strike last month, US officials say.

Abu Saleh was killed in late November, US military spokesman Colonel Steve Warren said on Thursday in a videoconference from Baghdad, calling him “one of the most senior and experienced members” of the group’s financial network.

The US government’s envoy for the anti-IS fight, Brett McGurk, said on Twitter that Abu Saleh was killed, along with two associates “as part of coalition campaign to destroy ISIL’s financial infrastructure”, describing him as the group’s “finance minister”.

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Abu Saleh’s real name is Muwaffaq Mustafa Muhammad al-Karmush, described in a State Department terrorist blacklist as a 42-year-old Iraqi.

“Killing him and his predecessors exhausts the knowledge and talent needed to co-ordinate funding within the organisation,” Warren said.

The military spokesmen said two other figures in IS fundraising networks were also killed in coalition air strikes in late November.

They were identified as Abu Mariam, an enforcer and senior leader in IS extortion networks, and Abu Waqman al-Tunis, who Warren said co-ordinated IS’s transfer of people, weapons and information.

In London, the US Treasury’s acting under secretary for terrorism and financial crimes, Adam Szubin, said IS derived most of its funding from economic activity in the territory it controls.

It has reaped more than $US500 million ($A690 million) in black market oil sales, looted bank vaults captured in Iraq and Syria, and raised millions more through extortion.

But to run what amounts to a mini-state, it needs steady and renewable sources of funding, and to do that it needs access to the international financial system to move money and import supplies, according to Szubin.

“We are targeting both of these dependencies – ISIL’s ability to generate revenue, and its ability to use that revenue,” he said.