Foreign legions are volunteer military units made up of international fighters. Most of these foreign soldiers are former servicemen with military experience. Examples of foreign legions include, but are not limited to, the Kurdish People's Protection Unit in Syria, Peshmerga in Iraq, and the most recent International Legion of Territorial Defense of Ukraine. In light of the recent Russian invasion of Ukraine, several South Koreans including South Korean former Navy Seal and YouTuber Ken Rhee has gone to Ukraine to fight the Russians. The Ministry of Foreign Affairs issued a warning in early March that citizens who enter Ukraine without permission are subject to criminal punishment and administrative restrictions.