GENEVA (Reuters) - Tanzania has naturalised 162,000 refugees from Burundi in what the United Nations refugee agency UNHCR said on Friday was a historic move that other countries should copy. A UNHCR spokeswoman said Tanzania's move was the most generous naturalisation anywhere. Tanzania's act gives citizenship to the bulk of the Burundians who fled to Tanzania in 1972, and their children. Most of them -- Hutus who fled ethnic violence in Burundi -- were no longer confined to refugee camps and were already largely integrated into Tanzania's society and economy, she said. U.N. High Commissioner for Refugees Antonio Guterres, who was in the East African country for the announcement, described Tanzania's move as a "historic action" and called on donor countries to respond by helping Tanzania integrate its new citizens. "The High Commissioner urged other countries with long-staying refugee populations to emulate Tanzania's unprecedented decision," the agency said in a statement. As recently as 2000 Tanzania had the largest refugee population in Africa, with over 680,000 refugees from Burundi and the Democratic Republic of the Congo. Most of them were Burundians who fled civil war in the 1990s, but since the peace process started in 2002, some 500,000 Burundians have returned home, including 360,000 from Tanzania, UNHCR said. The naturalisation leaves Tanzania with some 97,000 refugees in camps and settlements, mostly from Burundi or DR Congo, a UNHCR spokeswoman said.