UNITED NATIONS, Jan. 3 (Xinhuanet) -- UN Secretary-General Kofi Annan on Monday appointed Mark Malloch Brown, administrator of theUN Development Program (UNDP), as his new chief of staff in what he said part of a planned reshuffle of the world body's management.

    Annan announced the appointment at a press conference at the UNheadquarters in New York, presenting his new top aide as "immensely capable leader and manager."

    Brown will start on Jan. 19 to take the place of the 70-year-old Pakistani, Iqbal Riza, who will soon retire after having served at the post for seven years. His request for retirement wasaccepted by Annan last December.

    Annan said Brown, a 51-year-old Briton, will continue to head UNDP until his replacement is found.

    The UN chief added that he believed Brown's new posting will not have any "negative impact" on the UN relief operations in countries hit by the Indian Ocean tsunami.

    Brown had been vice president for external affairs of the WorldBank since January 1996 before taking the post of UNDP administrator in July 1999.

    Annan said he will reshuffle the UN senior management to pursuein the next two years his two top priorities, UN reforms and the implementation of millennium development goals.

    Other senior UN officials who decided to leave are Catherine Bertini, under-secretary-general for management, and Jean-Pierre Halbwachs, the UN controller.

    Bertini, who has been the top UN management official since January 2003, is expected to leave early this year. Enditem