MOSCOW (AP) - Ukraine's military says a Ukrainian air force pilot has died when his Sukhoi Su-27 fighter jet crashed while attempting to land at a base in the northern region of Zhytomyr.

The Ukrainian General Staff wrote on its Facebook page that the plane went down Saturday during a routine flight. An investigation into the crash is underway.

Su-27 fighter jets were designed by the Soviet Union and continue to be built by Russia. Depending on the model, they carry either one or two pilots. It was not immediately clear what the model was in Saturday's crash.

Ukraine lost a two-seat Su-27 in October during exercises with the U.S. Air National Guard. An American pilot, riding in the second seat, died along with his Ukrainian comrade.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.