Sukhoi No. 135 in Kharkiv, Ukraine. However, Sukhoi was not satisfied with its location, since it was isolated from the scientific pole of Moscow. Sukhoi later relocated the bureau to the aerodrome of Podmoskovye in Moscow, completing half of the relocation by 1940. Sukhoi encountered another issue: the bureau had no production line in Moscow, thus making it useless as Sukhoi had nothing to do. During the German invasion of the Soviet Union in World War II, the Su-2 needed a successor as it was proved obsolete and under-armed against German aircraft, with 222 aircraft destroyed in total. Sukhoi and his
Sukhoi Su-27 by the Japan Ministry of Defense. Russia denied the incursion, saying the jets were making routine flights near the disputed Kuril Islands. In another encounter, on 23 April 2014 an Su-27 nearly collided with a United States Air Force Boeing RC-135U over the Sea of Okhotsk. Russia plans to replace the Su-27 and the Mikoyan MiG-29 eventually with the Sukhoi Su-57 stealth fifth-generation multi-role twin-engine fighter. A squadron of Su-27SM3s was deployed to Syria in November 2015 as part of the Russian military intervention in the Syrian Civil War. Ethiopian Su-27s reportedly shot down two Eritrean MiG-29s and damaged another