Ukraine’s domestic security agency has arrested an air force officer accused of spying for Russia by leaking the locations and flight schedules of Western-supplied fighter jets, officials said Wednesday.

The officer, identified only as a major in one of Ukraine’s air brigades and a flight instructor, was allegedly working as an agent for Russia’s military intelligence agency, Ukraine’s Security Service (SBU) said Wednesday. He is suspected of helping coordinate missile and drone attacks against key Ukrainian air bases.

The officer is accused of gathering data on the locations and schedules of Ukrainian jets — including U.S.-made F-16s and French Mirage 2000s — and advising Russian forces on how to bypass Ukrainian air defenses, the SBU said in the Telegram post.

The F-16 and Mirage 2000 fighters are viewed as critical reinforcements for Ukraine’s air defenses as Russia ramps up its aerial attacks across the country.

The suspect also allegedly shared personal details of Ukrainian pilots, along with information on the weaponry and combat tactics of the aircraft.

He was detained while attempting to collect more intelligence and was charged with treason. If convicted he faces life imprisonment, according to the statement.

The arrest follows the detention earlier this month of two Chinese nationals suspected of spying on Ukraine’s Neptune missile program, a key part of its domestic defense industry.