The Russo-Ukrainian War has seen a significant amount of foreign fighters join both sides of the conflict. It had been estimated prior to the 2022 Russian invasion of Ukraine that there were approximately 17,000 foreign fighters in Ukraine. Foreign fighters have travelled to fight in the conflict for a variety of reasons, such as far-left or far-right ideologues supporting their perceived ideological allies, religious and ethnic affinities, opposition to Russia or the West and those seeking to do so for "recreational" purposes. Before February 2022, Russia had sought to obscure its direct involvement in the War in Donbass (and initially the annexation of Crimea) by stating its forces were foreign volunteers and unaffiliated with its official military forces.