NATO surveillance planes have flown their first mission in support of the coalition battling the "Islamic State of Iraq and the Levant" (ISIL), alliance head Jens Stoltenberg said Tuesday (October 25th).

NATO leaders agreed in July to commit the AWACS surveillance aircraft, which Stoltenberg said had conducted their first flight last Thursday, AFP reported.

NATO was "committed to sustaining the coalition's momentum so that ISIL can be defeated once and for all", he said, ahead of a two-day defence ministers meeting in Brussels.

All 28 NATO members also belong to the anti-ISIL alliance, but some were reluctant to see the coalition directly involved in the Syrian conflict, so the aircraft were limited to flying in international airspace or over NATO member Turkey.

Stoltenberg said while he could not comment on their exact role, the aircraft "will not be part of combat operations".

AWACS have powerful radars that allow them to monitor airspace for hundreds of kilometres. They can also serve as command posts to co-ordinate bombing raids and other operations.