Hundreds of millions of dollars are believed to have been destroyed in coalition air strikes targeting cash hoards used to finance the Islamic State group, a US military spokesman said Wednesday.

Coalition aircraft struck ten more of the cash collection points over the weekend, said Colonel Steve Warren, the spokesman for the US-led campaign against IS in Iraq and Syria.

"We don't have a hard number that we're prepared to release. We believe it is in the hundreds of millions of dollars," Warren told Pentagon reporters in a video conference from Baghdad.

"Obviously it is impossible to burn up every single bill. So presumably they were able to collect a little bit of it back. But we believe it was a significant series of strikes that have put a real dent in their wallet," he said.

Targeting the cash hoards is part of a broader strategy to disrupt the group's sources of revenue.

Coalition aircraft also have been hitting oil infrastructure under IS control as part of the effort.

Warren said the impact can be seen in reports that IS has had to cut salaries paid to its fighters, sometimes by as much as half.

"So this to us is a very significant indicator that these strikes against their ability to generate revenue are beginning to squeeze them a little bit," he said.

IS shoots down Iraqi army helicopter killing one
Baghdad (AFP) Feb 17, 2016 - The Islamic State jihadist group shot down an Iraqi military helicopter west of Baghdad on Wednesday, killing at least one person, officials said.

The helicopter -- the second lost by Iraq in two days -- went down near Amriyat al-Fallujah, though officials differed on the exact location.

An Iraqi army aviation captain said that the Bell helicopter was shot down with a Dushka heavy machine gun, killing one crew member and wounding a second, who was rescued by another helicopter.

Lieutenant Colonel Arif al-Janabi, the police chief for Amriyat al-Fallujah, said that IS shot the helicopter down, putting the death toll at two.

Shakir al-Essawi, the head of the area's local council, confirmed Janabi's account.

IS issued an online statement claiming that it shot a helicopter down and damaged another in the Amriyat al-Fallujah area on Tuesday.

Iraq has lost multiple helicopters to accidents and ground fire in recent years, while others have been damaged.

An Iraqi Mi-17 helicopter crashed south of Baghdad due to a "technical problem" on Tuesday, killing nine people.

In October 2014, militants shot down a Bell 407 north of Baghdad, killing two crew, five days after an Mi-35 was shot down in the same area, while jihadists destroyed another helicopter on the ground earlier in the year.

An overloaded helicopter crashed after delivering aid to people besieged by the Islamic State jihadist group on Mount Sinjar in August 2014, killing its pilot and injuring passengers, including a member of parliament.

Lieutenant General Hassan Karim Khudayr was killed when a military helicopter crashed north of Baghdad before IS launched a sweeping offensive in June 2014. Iraq also lost an Mi-17 to a sandstorm in July 2010, a crash that killed five.