US President Barack Obama has said that a video purportedly showing the burning alive of a Jordanian pilot shows the barbarity of the Islamic State that has seized swathes of territory in Iraq and Syria.

"Today, we join the people of Jordan in grieving the loss of one of their own, First Lt Moaz al-Kasasbeh, cruelly and brutally killed by ISIL terrorists," he said in a statement.

Obama later met King Abdullah II of Jordan at his office. Along with his compatriots and other Arab and international members of the anti-ISIS coalition, al-Kasasbeh was in the vanguard of the effort to degrade and defeat the threat posed by the terror group, Obama said.

"Al-Kasasbeh's dedication, courage, and service to his country and family represent universal human values that stand in opposition to the cowardice and depravity of ISIL, which has been so broadly rejected around the globe. As we grieve together, we must stand united, respectful of his sacrifice to defeat this scourge," he said.

"Today, the coalition fights for everyone who has suffered from ISIL's inhumanity. It is their memory that invests us and our coalition partners with the undeterred resolve to see ISIL and its hateful ideology banished to the recesses of history," Obama said.