The Geneva Conventions and their Additional Protocols are at the core of international humanitarian law, the body of international law that regulates the conduct of armed conflict and seeks to limit its effects. They specifically protect people who are not taking part in the hostilities (civilians, health workers and aid workers) and those who are no longer participating in the hostilities, such as wounded, sick and shipwrecked soldiers and prisoners of war. The Conventions and their Protocols call for measures to be taken to prevent or put an end to all breaches. They contain stringent rules to deal with what are known as "grave breaches". Those responsible for grave breaches must be sought, tried or extradited, whatever nationality they may hold.