He earned a high international profile when , in the aftermath of the killing of fourteen unarmed civilians in Derry by British Paratroopers ( known as `` Bloody Sunday '' ) , he traveled to the UN in New York to demand UN involvement in peace-keeping on the streets of Northern Ireland .
After `` Bloody Sunday '' ) , he traveled to the United Nations in New York to demand UN involvement in peace-keeping on the streets of Northern Ireland .