Turkish President Recep Tayyip Erdogan warned European nations Tuesday that his country could release all the ISIS group prisoners it holds and send them to Europe, in response to EU sanctions over Cyprus. Speaking to reporters before a visit to the United States, Erdogan also said Turkey would continue repatriating foreign ISIS militants to their home countries, even if those countries decline to take them back. Ankara began deportations on Monday. Erdogans comments were in response to the EUs unveiling on Monday of a system for imposing sanctions on Turkey over its unauthorized gas drilling in Mediterranean waters off Cyprus. Erdogan warned EU countries: "You should revise your stance toward Turkey, which holds so many ISIS members in prison and controls them in Syria." Turkey, which is a formal candidate to join the EU, says it is operating in waters on its own continental shelf or areas where Turkish Cypriots have rights. EU ministers said in a statement that Monday’s decision “will make it possible to sanction individuals or entities responsible for or involved in unauthorized drilling activities of hydrocarbons in the Eastern Mediterranean.” Cyprus was divided in 1974 after a Turkish invasion triggered by a brief Greek-inspired coup. Several peacemaking efforts have failed and the discovery of offshore resources has complicated the negotiations.