Militants are reported to have downed an OSCE monitoring drone / Photo from

Daniel Baer, the U.S. ambassador to the Organization for Security and Cooperation in Europe (OSCE), said on Twitter on Monday that the militants had used a signal jammer to bring down a drone.

The OSCE is mandated under the Minsk protocol on halting the Donbas conflict to use drones to monitor the situation in the conflict zone, in particular the situation on Ukraine’s eastern border with Russia.

“The head of the [OSCE’s] Special Monitoring Mission (SMM) Ertugrul Apakan said the OSCE drone crashed after the use of a signal jamming device, when militants attacked a Ukrainian checkpoint on October 29," Baer wrote.

Later on Monday, Baer wrote that militants had also shot at another unmanned aerial vehicle (UAV or drone) operated by the OSCE.

“Numerous anti-aircraft rounds were fired at an SMM UAV on 2 Nov. But UAV left the area, landing SAFELY,” Baer tweeted.