He said he could also hear the sound of antiaircraft fire but wasn 't sure if there were any coalition fighter planes overhead .
他说他也能听到防空炮弹的声音,但不确定上空是否有多国部队的战斗机。
Turkey has repeatedly said its jet was downed in international airspace and one mile ( 1.6 kilometers ) outside syrian territorial waters , comfortably out of the range of an antiaircraft battery .
Mr. assad reiterated syria 's account of the incident , claiming the turkish rf4 jet was downed on syrian territorial waters and by antiaircraft gunfire , not with a surface-to-air missile , as turkey has claimed .
Conventional truck bomb attacks against bridges , antiaircraft missile shots at civilian airliners , the proliferation of chemical , biological , or nuclear weapons that leads to their use by terrorists - every one of these other terrorist threats is nontrivial .