The family of James Foley had critical words for the government's handling of his case, with the murdered journalist’s brother telling Fox News the Obama administration threatened him when he tried to raise funds for his brother's release from ISIS -- the terrorist group that beheaded him in an Internet video that shocked the world.

"They were actually an impedance," Michael Foley told FNC’s Megyn Kelly of the U.S. government's role in rescuing his older brother, a photojournalist who was kidnapped by ISIS militants in northern Syria in 2012 and held captive for 21 months before he was executed by the terrorist group.

U.S. policy does not allow for government negotiations with terrorist organizations or ransom payments for Americans kidnapped by them. Foley, however, said the administration made it difficult for the family to privately raise funds on its own to secure his brother's release.

Foley's parents, in a separate interview with Greta Van Susteren, were less critical, although Diane Foley said she felt the government could have done more to save her son.

"The only response we got from the government was, 'Trust. Trust us, we're working on it,' " she said in an interview set to appear later Friday on FNC's "On the Record w/ Greta Van Susteren."

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"As a frantic mother I did my best to trust … I did my best. I did best to make myself a pest so that they wouldn’t forget us. We didn't get the attention [from the government] until the end but it was too late," Diane Foley said.

Michael Foley, James' younger brother, was more forceful in his criticism of the administration. 

"They got in our way," Foley told Fox News' Megyn Kelly in an exclusive interview Thursday. "That's what really bothers me to the core."

"I was specifically threatened by the Department of State about raising funds towards ransom demands for my brother," he said. "We were smart enough to look past it but it slowed us down. We lost a lot of time."

On Aug. 19, a video produced by ISIS militants was uploaded to YouTube titled, "A Message to America." Foley, an experienced war journalist who worked for Boston-based GlobalPost, is seen in the video in an unknown desert location kneeling in an orange shirt and pants -- similar to clothes worn by Guantanamo Bay detainees. After reading a statement denouncing the U.S. government and its recent air strikes in the region, Foley is executed.

The murderer, who speaks with a British accent, then threatens to kill U.S. journalist Steven Sotloff, who had also been abducted in Syria. On Sept. 2, a video was released of ISIS beheading Sotloff, who had worked for Time magazine as well as Christian Science Monitor and other media outlets.

In the days following Foley's execution, the White House said special operations troops were deployed to Syria months earlier on a secret mission to rescue U.S. hostages, including Foley, but were unsuccessful in finding them. 

"Since his capture, we have been using every tool at our disposal to try to bring him home to his family and to gather any and all information we could get about his whereabouts, his condition and the threats he faced," White House spokeswoman Caitlin Hayden said last month.

While the U.S. and U.K. do not pay ransom for citizens kidnapped by terrorist groups, other countries, like France, have reportedly negotiated in secret for the release of hostages. 

Didier François, a reporter with French radio Europe 1, was released by ISIS after months of captivity in April 2014. He later told reporters he shared a cell with Foley from September 2013 up until his release. France has denied reports that it paid $18 million for the release of François and three other journalists. 

According to a GlobalPost spokesman, Foley's captors had demanded a ransom of about $135 million for his release.

President Obama addressed the nation Wednesday, on the eve of the anniversary of the Sept. 11 attacks, authorizing U.S. airstrikes in Syria along with expanded airstrikes in Iraq and vowing to wipe out the group’s terrorists "wherever they exist."

"Our objective is clear: we will degrade, and ultimately destroy, ISIL through a comprehensive and sustained counter-terrorism strategy," Obama said during a 15-minute, prime-time address.

The president's speech effectively completed a dramatic turnaround from the administration's approach to the Islamic State just a few months ago, when the president downplayed the group's advances through northern Iraq. Now, he is outlining a "comprehensive" strategy for targeting the organization in Iraq and Syria, including by potentially aiding moderate factions of the Syrian opposition.

For Michael Foley, the president's words, "didn't sound like much of a plan to me." Foley said Obama's new military campaign, "certainly came too late for Jim."

"I just hope it's not too late for others," Foley told Fox News, adding that "I can't wrap my mind around" the "evil" shown in his brother's execution video. 

"Jim was such a good person ... He really cared about the disadvantaged his entire career," he said. His older brother's murder was "an ending I just could never have imagined."

"Because he was American, he was the whipping boy," Diane Foley said. "He went through some horrible things. … We’re just learning about this now."

While Foley's family expressed their criticism of the administration's handling of the case, his father, John, made clear that, "We don’t want to blame our government. They’re not the enemy. ISIS is the enemy."

John and Diane Foley will appear on Fox News Channel's "On the Record w/ Greta Van Susteren" Friday night. 

To watch the entire interview, tune into "On The Record with Greta Van Susteren" at at 7 p.m. EST.