Armed Russian jets violated the US airspace over Tanf base in Syria 25 times so far in March, a senior US general told NBC on Wednesday, adding that a main concern is a “miscalculation or unprofessional or immature action by somebody” in light of the incident of the US drone crash into the Black Sea after being intercepted by Russian fighter jets.

Lt. Gen. Alexus Grynkewich, combined forces air component commander for US Central Command, said in the interview that the Russians violated a years-old agreement between the US and Russia, risking escalation.

The US and Russian militaries had signed a memorandum of understanding (MoU) that set out air safety procedures in Syrian skies to avoid any accidents or encounters between the two forces’ jets.

“The Russians have over the last several months seemed to abandon that tenet of the protocols,” Grynkewich said.

To put the number of Russian flights over the US airbase in perspective, the US commander said there were zero violations in February, and 14 in January. Grynkewich said it was a “substantial increase” and that if the Russians kept up this rate they would be “on track to be double what has been in the past”.

“They’re regularly flying directly overhead of our units, and I’ve defined directly overhead, as within about a mile, no more than a mile offset one side or the other, while we’ve got forces right there on the ground at ATG [al-Tanf Garrison],” Grynkewich told NBC, adding: “So, it’s an uncomfortable situation.”

The commander said the violations “increase the risk of miscalculation,” adding: “and given things like the MQ-9 incident in the Black Sea, it’s not the kind of behavior that I’d expect out of a professional Air Force.”

A US military surveillance drone (MQ-9 Reaper) crashed into the Black Sea on March 14 after an encounter with Russian Su-27 fighter jets in international airspace near territory Russia claims to have annexed from Ukraine.

The US and Russian offered different versions of events diverging over the cause of the drone’s crash. The US maintains that a Russian Su-27 jet clipped the propeller of the drone which led to the crash; while Russia denies any physical contact between its jets and the drone, and says, “the device went out of control as a result of sharp maneuvering,” then crashed.

This was the first such incident between Washington and Moscow since the latter launched its invasion of Ukraine in February 2022.

On Monday, the Russian defense ministry said a Russian Su-35 fighter jet was scrambled over the Baltic Sea to intercept two US B-52H strategic bombers flying towards the Russian border. Washington denies the incident took place.

The general explained that US forces or international coalition against ISIS forces respond to the Russian aircraft, usually by shadowing them from a distance. However, he warned that if they had to respond to a Russian flight during an ongoing US military operation on the ground, the mission could be in jeopardy.

“What it is really is a distraction from the fight against ISIS,” Grynkewich said. “It hasn’t affected the fight on the ground yet, but it certainly has the potential to… I’m not concerned about overt hostilities; I’m concerned about a miscalculation or unprofessional or immature action by somebody.”