Syrian warplanes were dropping bombs just "several hundred meters" away from U.S. Special Forces troops operating alongside Kurdish troops on Aug. 18, a top U.S. general said Tuesday. 

Army Gen. Joseph Votel, head of U.S. Central Command, spoke publicly for the first time about the unprecedented incident that sparked a standoff between the U.S. and Syrian air forces. 

"I think [the Syrian bombs] were several hundred meters away from areas in which we were, close enough to be concerned but it wasn't an immediate direct threat," Votel told reporters at the Pentagon Tuesday. 

The Aug. 18 incident was the first time the Syrian Air Force threatened the roughly 300 U.S. troops who are operating on the ground in Syria.

The incident prompted the U.S. to scramble fighter jets into the air over the town of Hasaka, but the Syrian Su-24s had departed the area before the U.S. aircraft arrived, defense officials said. On the following day, two U.S. F-22 aircraft intercepted Syrian Su-24 combat jets flying through the same area, defense officials said. 

The Syrian airstrikes failed to strike or injure any U.S. troops. But the incident was especially troubling because Syrian warplanes typically use so-called "dumb bombs" that lack the sensors for precision targeting. 

Votel said Tuesday he was unsure why the Syrian's mounted the attack on the U.S. forces, who have been operating in that part of Syria for several months. U.S. military officials say the Syrians were aware that U.S. troops were operating in the area. 

"I'd just be speculating on what their motivations might be," Votel said. 

The U.S. forces are advising Kurdish militants who are fighting Islamic State militants in Hasaka, a key transit point between Mosul and Raqqa, the two major cities of the Islamic State group's territory.   

The incidents with the Syrian aircraft prompted the Pentagon to issue a clear warning for Syrians and others to stay away from U.S. forces. 

"It's not a no fly zone," Peter Cook, a Defense Department spokesman, told reporters on Aug. 22.  

"But," Cook added, "the Syrian regime would be wise to avoid areas where coalition forces have been operating. And we will continue defend them and, if need be, we will send aircraft again to defend our forces."