Retired Marine Corps Gen. John Allen has warned that the United States should take threats from the Islamic State very seriously, but emphasized that the brutal burning death of a Jordanian pilot has backfired on the terrorist group.

"ISIS at an entirely different level [than al Qaeda]. It's better organized, has better situational awareness," Allen told ABC's "This Week." "It has redefined barbarity."

General Allen, who is the Special Presidential Envoy for the Global Coalition to Counter ISIS, added that the release of a video showing Jordanian pilot Lt. Muath al-Kaseasbeh being burned to death in a cage has prompted forces opposing ISIS, Jordanian King Abdullah in particular, to seek out and destroy the group with greater determination.

"The coalition [against ISIS] is strengthening daily," Allen said, "It will be one of these moments that created a unity of purpose and a unity of effort among the nations [of the world.] King Abdullah has indicated the desire to do more in the aftermath of this horrific killing. He's been a leader in this process...It's a very important moment for our Arab allies in the coalition".

The General said that prior to the video's airing, the United States carried out nearly 80 percent of the airstrikes against ISIS targets. But on Thursday,  Jordan initiated its own wave of airstrikes which continued for three days. According to reports, many of the Jordanian pilots wrote, "ISIS is an enemy of Islam" on their bombs.

The Islamic State, which currently controls about a third of Iraq, will likely continue to work against itself with stunts like airing the video, General Allen asserted. He also said that the group is prompting foreign fighters to join the coalition against them.

"[ISIS] is beginning to eat itself with increasing numbers of reports of ISIL executing foreign fighters who have come from long distances to be part of this," he said.

Last week, the terrorist group claimed that Jordan's recent airstrikes killed the last remaining U.S. hostage in the terrorists' possession, humanitarian aid worker Kayla Mueller. However, Allen said that while the U.S. and Jordan are still investigating, there is little evidence ISIS' claim is valid.

On Thursday, John Boehner, Republican Speaker of the US House of Representatives, said he believed U.S President Obama will soon seek congressional authorization for using increased military force against ISIS, and also called for speeding up assistance to Jordan.

"It is also going to be incumbent upon the president to go out there and make the case to the American people," he said.