When Israel starts shooting at Russian aircraft, it’s time to worry.

But that’s what happened last month, when a Russian drone accidentally—or allegedly accidentally—flew from Syria into northern Israel. Israeli forces attempted to shoot down the drone, marking the first time that Israel has fired on Russian forces operating in Syria.

The incident occurred on July 17, when a Russian drone took off a Syrian air base near Damascus, according to an Israeli Air Force investigation cited in Israeli newspaper Ha’aretz. The drone crossed the Israel–Syria border over the Golan Heights and then flew southwest, where it flew in circles—as military drones do when performing surveillance missions—over a kibbutz in the Galilee near Kiryat Shmona.

Someone in the Israel Defense Forces had enough sense to contact the Russian military over a special hotline established precisely to avoid border incidents. “There were at least seven phone calls in the course of about twenty minutes, but to all of them the Russians replied that none of their drones had crossed into Israeli territory,” Ha’aretz reports.

By then, the Israelis had confirmed the intruder wasn’t one of their drones, which left the possibility that it belonged to Hezbollah’s growing drone fleet. Never shy about using force to protect their airspace, Israeli forces scrambled two F-16s and launched Patriot antiaircraft missiles to destroy the drone.

“One of the planes launched a missile but missed the target,” Ha’aretz writes. “The IAF [Israeli Air Force] aerial defense system was also activated, but the Patriot batteries were unable to intercept the drone. There was a problem with one of the missiles fired by the battery, while the second missile missed the target. The planes chased the drone when it backtracked eastward, toward the Syrian border, but didn’t hit it, and the drone flew into Syrian territory.”