AMMAN (AFP) - Jordanian state television on Tuesday said pilot Maaz al-Kassasbeh, whom the Islamic State in Iraq and Syria (ISIS) group claimed to have burnt alive in a video posted online, was killed a month ago.

It said the captured airman had been killed by the group on Jan 3, before the militants offered to spare his life and free a Japanese journalist in return for the release of a female would-be suicide bomber on death row in Jordan.

The extremists had threatened to kill Kassasbeh unless Amman handed over Iraqi radical Sajida al-Rishawi.

Jordan had insisted on proof that the pilot, captured on Dec 24 after his F-16 jet went down while on a mission over northern Syria, was alive before any exchange.

State television broadcast a picture of "martyr pilot Kassasbeh" with a black band across the screen accompanied by patriotic music.