UN Secretary General Ban Ki-moon on Monday asked Angola to provide helicopters for peacekeeping missions in countries including the Democratic Republic of Congo and South Sudan.

"As you know, several of our peacekeeping missions including MONUSCO in DRC and UNMISS in South Sudan, they suffer from a lack of a military helicopters. I would appreciate it if your government" could assist, Ban said during a meeting with Angolan Foreign Minister Georges Chikoti in Luanda.

"The secretary general asked the Angolan government to consider providing military assets, including helicopters, to UN peacekeeping," Ban's spokesman Martin Nesirky told journalists.

The UN Mission in the Republic of South Sudan (UNMISS) is the successor to the six-year peacekeeping mission deployed in Sudan after the 2005 peace deal that led to South Sudan's independence from the north in July 2011.

It is tasked with consolidating the tenuous peace in the world's newest country, under threat from ethnic conflict, flaring border tensions with the rump state of Sudan and an unresolved dispute over oil transit fees.

Ban complained last month that he had been reduced to begging governments for helicopters and still could not get peacekeepers to the besieged South Sudan town of Pibor, where the UN says dozens and perhaps hundreds died in clashes between the Lou Nuer and Murle ethnic groups.

The mission was left short when Russia withdrew four of its UNMISS helicopters and grounded four others after an attack, Ban said.

The UN has access to 24 civilian helicopters in South Sudan, but they are normally not used for troop deployments.

The UN Stabilisation Mission in the Democratic Republic of Congo (MONUSCO), created in 2010 to succeed a peacekeeping mission deployed since 1999, is charged with protecting civilians and humanitarian workers from marauding rebel groups in the east.

It is one of the largest UN peacekeeping operations in the world, with some 20,000 uniformed personnel.