(AntiWar.com Jason Ditz) The US has confirmed that in an incident Sunday evening a US warplane, the F/A-18E Super Hornet, shot down a Syrian government Su-22 bomber south of Tabqa. The US accused the Syrian jet of having dropped bombs on Kurdish fighters in the town of Ja’Din.

The US has been increasingly attacking pro-government forces in eastern Syria, but this is the first time that they’ve shot down a manned Syrian aircraft, and the fact that it happened within Syrian airspace is likely to dramatically add to the tensions between the two sides.

The Pentagon argued that because they are allied with the Kurds they were free to attack the Syrian plane under the concept of “collective self-defense,” and added that they “will not hesitate” to take further military action to defend the Kurds, or other partnered forces, from future threats.

The Syrian Army said their operation was part of an ongoing push into ISIS-held territory, and that they view the US attack as a “flagrant” attempt to undermine their anti-ISIS operations. They added that the pilot of the destroyed plane is still missing after the US attack.