HELSINKI (Reuters) -Nobel Peace laureate Martti Ahtisaari, who served as Finland's 10th president between 1994 and 2000, died on Monday at the age of 86, the Finnish president's office said in a statement. Ahtisaari was celebrated around the world for brokering peace in conflict zones in Kosovo, Indonesia and Northern Ireland. His global fame boosted the image of Finland as it emerged from the shadow of the former Soviet Union.