UNITED NATIONS, Jan 28: The beleaguered UN Secretary General Kofi Annan received endorsement of his leadership by seventy Nobel Prize laureates including former US President Jimmy Carter on Thursday.

"He has never failed to take a critical look at the UN to examine its weaknesses and recommend improvements," the prize winners said in a statement released by the non-profit New York-based Better World Campaign.

"We commend Secretary General Kofi Annan for effectively leveraging his moral authority, independence, and wisdom to elevate the United Nations to meet its highest principles," the letter said.

Mr Annan's role in the Iraq oil-for-food programme has come under scrutiny and some conservative US law makers have called for his resignation. The UN chief "trusts that he can count on them to use their expertise in their respective fields to further the goals of the United Nations," it said in a statement.

Mr Annan, who shared the 2001 Nobel Peace Prize with the United Nations, was this week questioned for a third time by a commission he appointed to investigate mismanagement of the $67 billion UN oil-for-food programme.

Those signing the statement included winners for their work in peace, medicine, literature, physics, chemistry and economics. On the list were authors Nadine Gordimer, Gunter Grass of Germany, Toni Morrison, Seamus Heaney and Elie Wiesel. Also signing the document were Kim Dae-Jung, the former South Korean president and economist Joseph Stiglitz.