A man purported to be Islamic State captive Muath al-Kaseasbeh, a Jordanian pilot, stands in front of armed men in this still image from an undated video that was filmed at an undisclosed location and made available on social media Tuesday. (Via Reuters)

The Islamic State’s release on Tuesday of a video showing its fighters burning alive a captured Jordanian pilot sparked street protests calling for vengeance and threatened to draw this country’s usually low-key monarch toward ever more direct confrontation with radical Islam.

The Jordanian military, a close ally in the U.S.-led coalition against the Islamic State, vowed “punishment and revenge” for the killing, which it said had probably been carried out in early January.

The Jordanian public was stunned by the brutality of the videotaped slaying, the latest killing of a hostage by the Islamic State. The previous cases were all beheadings, but the latest video appeared to show the captive, Lt. Muath al-Kaseasbeh, 26, doused with flammable liquid and burned alive in a cage.

Before his death, many Jordanians were calling for the country to withdraw from the U.S.-led offensive against the Islamic State, arguing that it was not their fight. But the confirmation of Kaseasbeh’s death seemed to cement resolve here, and many Jordanians demanded that terrorist convicts sought by the Islamic State in a prisoner swap be immediately executed.

Early Wednesday, a government minister said Jordan executed two prisoners, including an Iraqi woman who was a failed suicide bomber and was sought by the Islamic State in a prisoner swap. Sajida al-Rishawi and Ziad al-Karbouli were hung at dawn, Information Minister Mohammed Momani said. Rishawi has been on death row for her role in a triple hotel bombing in the Jordanian capital, Amman, in 2005 that killed 60 people.

Local media reports earlier said authorities transferred two terrorist convicts — al-Qaeda-linked militants on death row who were said to be part of prisoner-swap talks between Amman and the Islamic State and already sentenced to death — to the Swaqqa Correctional Facility in central Jordan, where executions are carried out.

In a pre-recorded address to the nation late Tuesday, King Abdullah II condemned what he called the “cowardly” act and urged national unity in a time of grieving. He called the Islamic State “that criminal organization that has no ties to our religion.”

Abdullah was in Washington to discuss a new aid deal with the United States. After learning of the killing, he cut short his visit, heading to the airport after stopping at the White House to meet with President Obama.

Momani warned that Jordan’s response to the killing will be “strong.”

“The brutal killing of the captive pilot is proof of the cruelty of this terrorist and fanatic group,” Momani said.

Jordanians focused, too, on the fact that the militants, who claim to adhere to a strict interpretation of Islam, had tortured and executed a fellow Muslim.

“This execution was un-Islamic in every sense,” said Mohammed Shalbi, or Abu Sayyef, head of the hard-line Jordanian Salafist movement, which maintains ties with the Islamic State and al-Qaeda.

The pilot “was Muslim, his parents were Muslims and he was a prisoner of war,” the cleric said. “This killing has proven that the Islamic State are deviants from Islam, and now all of Jordan — Islamists and liberals, East Bank and West Bank — are all united against them.”

U.S. response

In Washington, Obama said the United States and its coalition partners would “redouble” their determination to defeat the Islamic State, but U.S. officials said they did not envision any expansion or change in the current strategy.

“We’re going to remain committed to this, as we have been, and there’s not going to be any loss of focus,” said Rear Adm. John F. Kirby, the Pentagon press secretary. “It only makes it that much more important for us to succeed.”

Despite earlier calls in Jordan to reduce participation in the coalition, U.S. officials indicated a hope that Kaseasbeh’s slaying would increase Arab commitment and undercut the Islamic State’s appeal to disaffected Muslim youths around the world.

“That a young patriot — a devout Muslim, one of eight children, just months into married life, with hopes of his own family in front of him — would be ISIL’s latest victim reminds us all of the evil of this enemy,” Secretary of State John F. Kerry said in a statement, using one of several acronyms for the Islamic State.

Last week, the Jordanian government said that in exchange for Kaseasbeh, it was ready to free Rishawi, but officials demanded that the Islamic State provide proof that the pilot was still alive. It did not.

A Japanese journalist held by the Islamic State may also have been included in the deal, but any potential swap appeared to unravel after a video was released Saturday that showed the beheading of the reporter, Kenji Goto.

Timing of death

On Tuesday, the Jordanian Armed Forces issued a statement saying that Kaseasbeh had been killed on Jan. 3. It did not explain how it determined the timing, which, if correct, would mean the Islamic State was being duplicitous when it warned last week that Kaseasbeh would be killed if Jordan did not swap Rishawi for Goto.

Shortly after the video began circulating on social media, hundreds of Kaseasbeh’s relatives and supporters gathered at the family’s house in Amman.

The mourning session quickly turned into an anti-Islamic State rally, with participants chanting, “Terrorists will not scare us!” Protesters also gathered near Amman’s Interior Ministry and in Kaseasbeh’s home town of Karak, in southern Jordan, burning Islamic State flags and calling for revenge.

“All we want to see is the execution of all Islamic State members in our custody and outside in the same manner — burned alive,” said Fahed Jawazneh, a cousin of the pilot.

Adal Adaleen, another relative, said Jordanians were now “prepared for war.”

“The Islamic State proved through its crime that not only are they not Islamic, they are not human,” Adaleen said.

The pilot was captured in December after his plane crashed in Syria during a bombing run. Late last year, the Islamic State posted social-media images of Kaseasbeh surrounded by masked militants as his captors pulled him from a body of water.

Booth reported from Jerusalem. Karen DeYoung and William Branigin in Washington contributed to this report.