New York  - US President Barack Obama will host a special meeting for African heads of state when they attend the UN General Assembly in New York next week, a US official said Monday.

Obama will host a luncheon for presidents and prime ministers of sub-Saharan and African nations and invitations have been sent out, said US Ambassador to the UN Susan Rice.

"The luncheon will focus on building a 21st century partnership to increase social and economic development in Africa," Rice said.

Rice said Obama will also meet with countries that have contributed the largest number of police and troops to UN peacekeeping operations around the world.

"This is an opportunity for the president of the United States to recognize the largely unheralded contribution to the UN ... who have been doing essential work to build peace and security in fragile situations," she said.

The date and time of those meetings have not been made public.

Obama, who will make his first visit to the UN as US president, will take part on September 22 in a climate change summit and address the 64th UN General Assembly session the same day.

He will preside over a UN Security Council meeting on nuclear non- proliferation and nuclear disarmament on September 24. It will be the first time a US president will preside over the council because the US coincidentally holds the rotating presidency in September.

Obama has called for a world without nuclear weapons. But Washington has not yet ratified the Comprehensive Nuclear Test Ban Treaty, which can enter into effect only if all countries with nuclear technology in the world ratify it.  dpa