NATO aircraft were scrambled Sunday night to respond to a Russian attack on Ukraine, the Polish military said Monday.

A Ukrainian air force officer is said to have spied on the locations and deployment plans of the country's few Western fighter jets for Russia, Ukraine's SBU intelligence service has claimed. The major collected data on the F-16 aircraft from the United States,

A Ukrainian air force officer was arrested and charged with spying for Russia by leaking the locations of Kyiv’s prized F-16 and Mirage 2000 fighter jets, officials said. The officer, who was only identified as a flight instructor who held the rank of major,

A flight instructor for Ukraine's Air Force gathered information for Russia to help it prepare strikes on Ukrainian airfields, according to Kyiv. Ukraine's Security Service (SBU) said the unnamed major was arrested for passing on information to Russia to be used for strikes on sites hosting Western-supplied F-16 Mirage 2000 aircraft as well as Soviet-era Sukhoi-24 planes.