Former New Zealand prime minister Helen Clark will step down from her high-level role at the United Nations in April.
In a message to her staff, she said she would resign as director of the UN Development Programme (UNDP) on 19 April, the end of her second four-year term in office.
Miss Clark has been at the helm of the UNDP since 2009 and was the first woman to hold the position.
She said it had been a privilege and an honour to lead the organisation for eight years, and she would support the transition to its new leader.
Miss Clark ran for the role of UN Secretary General last year but did not perform well in early ballots and Portugal's Antonio Guterres was appointed.
She served as New Zealand's prime minister from 1999 to 2008.
Here is the full transcript of her email to her staff:
I am writing to advise all staff that I have informed the Secretary General that I am preparing to leave my position as Administrator at the end of my second term on 19 April.
This will allow the Secretary General to appoint a new Administrator as soon as possible. I stand ready to support the transition to the new leader of the organisation. I have full confidence in our Associate Administrator, Tege Gettu, to act as Administrator if there is a gap between my departure and the arrival of the next Administrator.
This is not my final message to staff - there is much to be done between now and 19 April. There is, for example, a timetable for tabling the draft of the next Strategic Plan to enable it to be discussed at the Executive Board's Annual Meeting on 31 May. It is my desire to see all aspects of the organization in a strong and sustainable state when the next Administrator assumes office.
These are times of change across the UN system. There are post-QCPR reviews being commissioned which may impact on UNDP. While these processes are unfolding, I urge you all to continue to deliver to the high standards for which UNDP is known. Making progress on the SDGs and on supporting national development achievements must continue unabated.
It has been a privilege and an honour for me to lead UNDP for eight years. Our staff are our greatest strength, and I will miss you all. I will offer my thanks and gratitude more fully nearer to my departure.