Martti Oiva Kalevi Ahtisaari ( pronounced ) ( born 23 June 1937 ) is a Finnish politician , former President of Finland ( 1994 â `` 2000 ) , Nobel Peace Prize laureate and United Nations diplomat and mediator , noted for his international peace work . Martti Oiva Kalevi Ahtisaari ( ; born 23 June 1937 ) is a Finnish politician , the tenth President of Finland ( 1994 â `` 2000 ) , Nobel Peace Prize laureate and United Nations diplomat and mediator , noted for his international peace work .