Antonio Guterres is set to seek a second five-year term as UN Secretary-General.
UN spokesperson Stephane Dujarric told reporters on Monday that Guterres had informed General Assembly President Volkan Bozkir of the move.
Guterres said in a letter to Bozkir that "he is available to serve a second term," if that would be "the will of the Member States."
Guterres sent a similar letter to the president of the Security Council.
Guterres has served as the prime minister of Portugal and UN High Commissioner for Refugees. He became the ninth secretary-general of the United Nations in January 2017, and his term is set to expire at the end of this year.
The top UN post is usually held for two consecutive terms. If Guterres is re-elected, he will face challenges such as the wealth disparity in the international community and global warming.