Jordan has executed by hanging an Iraqi female militant it had sought to exchange for a Jordanian pilot killed by Islamic State militants.
Government spokesman Mohammad al-Momani said authorities had also executed another Iraqi prisoner sentenced to death for terrorist plots.
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Profile: Sajida al-Rishawi
The executions were in response to the murder of Jordanian fighter pilot Maaz al-Kassasbeh, who was reportedly burned alive by the Islamic State group.
Hours after a video emerged online purporting to show the 26-year-old engulfed in flames, a security official said executions would begin at daybreak.
Would-be Iraqi female suicide bomber Sajida al-Rishawi was named as the first slated to go to the gallows.
Rishawi was sentenced to death for her role in a 2005 suicide bomb attack that killed 60 people.
Ziyad Karboli, an Iraqi Al Qaeda operative who was convicted in 2008 for killing a Jordanian, was also executed at dawn, Mr Momani said.
First Lieutenant Kassasbeh was captured in December when his jet crashed over northern Syria on a mission that was part of the US-led coalition air campaign against the jihadists.
Some Jordanians have criticised King Abdullah for embroiling them in the conflict they say was waged to serve the West's interests against Muslims.
Some also felt it could provoke a militant backlash.
Several politicians and lawmakers have called on the government to pull out of the coalition.
Jordanian authorities said First Lieutenant Kassasbeh's death would not weaken resolve to fight militant Islamist groups.
Obama leads international condemnation of pilot's murder
King Abdullah cut short a visit to the United States to return home following the announcement of First Lieutenant Kassasbeh's death on Tuesday (local time).
In a televised statement, he said the pilot's killing was an act of "cowardly terror" by a deviant group that had no relation to Islam.
King Abdullah, who was once in the military himself, described First Lieutenant Kassasbeh as a hero and vowed to take the battle to IS extremists.
"Jordan's response will be earth-shattering," information minister Mohammed Momani said on television.
"Whoever doubted the unity of the Jordanian people, we will prove them wrong."
Japan is with Jordan at this difficult time.
Japanese prime minister Shinzo Abe
US president Barack Obama condemned the murder and said it was clear the Islamic State group was only interested in death and destruction.
"Should in fact this video be authentic, it's just one more indication of the viciousness [and] barbarity of this organisation," he said.
Japan's prime minister, Shinzo Abe, said the apparent killing of Lieutenant Kassasbeh was "an unforgivable, outrageous act".
"I strongly condemn it," Mr Abe said in parliament.
"When I think about the feelings of his family, I am rendered simply speechless. Representing the Japanese government and people, I express here our sincere condolences.
"Japan is with Jordan at this difficult time. I am infuriated by these inhumane and despicable acts of terrorism."
Jordanian state television said First Lieutenant Kassasbeh had already been killed on January 3, before IS offered to spare his life and free Japanese journalist Kenji Goto in return for the release of Rishawi.
The beheading of journalist Kenji Goto was announced in a video posted late Saturday by Islamic State militants and came a week after his friend and fellow captive Haruna Yukawa was murdered.
ABC/wires
