Yuliy Valeriyovych Mamchur[a] (Ukrainian: Юлій Валерійович Мамчур) is a colonel in the Ukrainian Air Force who, for three weeks in March 2014, refused to abandon his post in Belbek, Crimea amidst the annexation of Crimea by the Russian Federation while surrounded and outnumbered by Russian forces.

[3][4][5][6][7][8] Mamchur is also credited for restraining amiably and diplomatically both his soldiers and pro-Russian forces from escalating tensions further, asking both sides not to shoot each other while the situation defuses.

[10] In the October 2014 Mamchur was elected into the Ukrainian parliament after being in the top 10 of the electoral list of Petro Poroshenko Bloc.

He instead chose to march to a pro-Russian checkpoint with his men unarmed while only carrying the flag of the 62nd Fighter Aviation Regiment.

The Russian troops eventually withdrew, while Mamchur, for twenty additional days, maintained his post in Belbek.

[14] Crimean separatists then cut the brakes in the family car, death threats he has received and in Sevastopol posters had been put up demanding his execution for treachery.

Mamchur was verbally abused by pro-Russian militia and cossacks, but he refused to be provoked, and ordered his men to resist non-violently and sing the Ukrainian national anthem.

[24] In August 2014 Mamchur was "working to restore combat efficiency" of this unit and restaffing it.

[9] According to Mamchur "Thirty-eight percent of my subdivision left Crimea, it is slightly more than 200 men".