President Obama may not be taking ISIS seriously — but the king of Jordan sure is, and he delivered a blistering speech to members of Congress that made him sound like a terror-fighting Dirty Harry.

King Abdullah told the House Armed Services Committee on Tuesday that he would wage “relentless” war against ISIS and wipe them out the way Clint Eastwood’s character in his Oscar-winning Western, “Unforgiven,” blew away his enemies.

“He said there is going to be retribution like ISIS hasn’t seen,” Rep. Duncan Hunter Jr. (R-Calif.) told the Washington Examiner. “He mentioned ‘Unforgiven,’ and he mentioned Clint Eastwood, and he actually quoted a part of the movie.”

The king’s tough talk came a day after ISIS thugs released a video of them burning a captured Jordanian pilot to death. The execution was filmed with Hollywood-quality camera work and effects.

Obama met with Abdullah on Tuesday to talk about the atrocity. But afterward, the president declined to mention Islamic extremism and used weak terms such as “bankrupt” and “vicious” to describe ISIS before quickly turning his comments to ObamaCare.

It wasn’t revealed which line from “Unforgiven” Abdullah quoted during his closed-door meeting with Congress.

But in the Oscar-winning 1992 film, Eastwood’s character, William Munny, pledges revenge against two cowboys who had attacked a prostitute. “Any man I see out there, I’m gonna kill him,” Munny says. “Any son of a bitch takes a shot at me, I’m not only going to kill him, I’m going to kill his wife and all his friends and burn his damn house down.”

After Abdullah’s rousing talk, Hunter said the king is “ready to get it on.”

“It reminded me of how we were after 9/11. We were ready to give it to them,” he told the Examiner.

Abdullah doubled down on his Eastwoodesque tough talk by later telling Jordanian television that he would stand for “values and human principles,” and declared that “our war . . . will be relentless and will hit [ISIS] in their own ground.”

A government spokesman added: “Jordan’s response will be heard by the world at large.”

The terror group released the video of the barbaric burning death of 1st Lt. Muath al-Kaseasbeh on Tuesday, but the execution is believed to have taken place Jan. 3 — before ISIS tried to use his release as a bargaining chip.

On Wednesday, they released another video, showing cheering Islamic State supporters — including children — watching the pilot’s immolation on screens in the ISIS-occupied Syrian city of Raqqa, the Daily Mail reported.

Titled “Muslims’ Joy at Burning of Jordanian Pilot,” the four-minute video shows crowds cheering and shouting religious slogans as they watch the pilot’s agony as he goes up in flames.

Meanwhile, a Pentagon source told The Post that officials are using “advanced techniques to glean as much information as possible to identify the extremists” seen in the execution video.

Additional reporting by Jamie Schram