Unconditional surrender is a surrender without conditions, except for those provided by international law. Announcing that only unconditional surrender is acceptable puts psychological pressure on a weaker adversary. The most notable uses of the term have been by the United States to the Confederate States of America in the American Civil War and to the Axis powers in World War II.
In the era post World War II, the comparable example of unconditional surrender is that of the Pakistani army in East Pakistan at the hands of the Indian army and the Mukti Bahini during the Indo-Pakistani War of 1971 or the latter half of Bangladesh Liberation War. Here 93,000 Pakistani soldiers surrendered unconditionally to the Indian Allied Forces (Mitro Bahini) commander Lt Gen. Jagjit Singh Arora.