(CNN)The U.S. and its allies are united in their air campaign against the terror group ISIS, but divided on the crucial question of whether or not to pay ransoms to free their captive citizens.
'Frank' disagreement among allies on hostage ransoms, British diplomat tells CNN
British and American officials tell CNN they have strong disagreements with some of their closest allies on the issue of ransoms, which their governments have long refused to pay.
Ransom payments, they maintain, are a form of terror financing and provide an incentive for terrorists to continue taking hostages. A senior British diplomat tells CNN his government makes this position "frankly" with allies who do chose to pay.
France, Italy and Turkey are among those who have been accused of paying ransoms to ISIS, al Qaeda and other groups.
Western officials told CNN they estimate that ISIS alone has earned nearly $40 million from ransoms, and the going rate for a single western hostage has risen to $6 million.
Sometimes the group asks for amounts so large, they are widely seen by analysts as symbolic rather than serious demands.
Earlier this year, ISIS demanded $200 million for the release of two Japanese hostages -- an amount equal to what Japanese Prime Minister Shinzo Abe had pledged for supporting anti-ISIS forces. Both hostages were ultimately executed.
And while the U.S. and U.K. continue to push for a universal no-ransom strategy, they haven't been able to stop all their international partners from making payouts.
"Kidnapping for ransom is financing a wide array of terrorist groups, including ISIL, and al Qaeda and its various affiliates," a State Department spokesperson told CNN Tuesday.
The policy has also drawn criticism from families of U.S. hostages, who fear the policy puts their loved ones in danger.
In an recent interview with the website BuzzFeed, President Barack Obama said he understands the frustration those families feel.
"You know, it's as tough as anything that I do, having conversation with parents who understandably want -- by any means necessary -- for their children to be safe," he said. "And we will do everything we can short of providing an incentive for future Americans to be caught."
This reassurance offers little comfort to some of those families, who are now pushing the administration to reconsider its policy.
Diane Foley, whose son, James, was the first American executed by ISIS on video, says she and her husband were warned not to give in to ransom demands when they brought the issue up with officials last year.
"We were told we could not raise ransom," said Foley. "That it was illegal. We might be prosecuted."
Law enforcement and administration officials say whoever told them that was wrong. The government won't pay ransoms, but for decades families and companies have paid ransoms and the government has never prosecuted anyone for doing it.
The Obama administration is currently undertaking a review of its hostage policy, and State Department spokeswoman Jen Psaki said last week "family engagement and involvement is part of that." However, changes to the ransom policy are not open for discussion.
According to former FBI lead international kidnapping negotiator Chris Voss, paying ransoms can sometimes be beneficial.
"Between point A and point B when you engage in this negotiation, you gather a lot of information about who they are, where they are, where they operate and how they operate," Voss told CNN. "These are sources of information we're not taping into in this process."
"Additionally, if you put a small amount of money in their hands then you then get the opportunity to find out all about how they spend money and who they are doing business with," he said.