The African heads of state meeting in Addis Abeba for the 20th African Union summit have postponed the signature of a regional peace agreement for the eastern DRC.

The signature by eight leaders from the region had been planned to take place on Monday.

"This is a very complex issue, talks are continuing," said Eri Kaneko, a spokesman for UN secretary general Ban Ki-Moon, without giving further details.

On Monday morning, President Paul Kagame and his Ugandan counterpart, Yoweri Museveni, helding a discreet meeting on the sidelines of the summit, an AFP reporter said. They were later joined by the Congolese President Joseph Kabila.

As Ban announced at the start of the summit, "the agreement for peace and security in the eastern DRC aims at tackling recurrent violence in the region." Diplomatic sources said it included reinforcing the UN mission in the DRC (Monusco) and a commitment by all governments in the region not to finance or support groups that destabilize the region.

Tanzania and South Africa have confirmed they are willing to contribute troops to an 'intervention brigade' that is supposed to be deployed alongside Monusco. UN officials recently indicated that this force could amount to 2,500 soldiers.

Meanwhile, in his address to the AU summit, President Paul Kagame has called on his African colleagues to double efforts in handling the crisis in Mali. "As Africans, we need to do more," he told heads of African states. "And doing more today is to significantly contribute to the funding and logistical requirements of AFISMA (African-led International Support Mission in Mali), as well as of the Malian Defense and Security Forces."

He also pointed out that the situation in Mali does not only concern that country itself. "The situation in the northern part of Mali threatens not only the security and stability of the country, but also that of the entire region and beyond," Kagame said. "Africa cannot, and should not, fold its arms when terrorist and criminal groups are occupying over half the territory of a Member State, carrying out the most atrocious crimes against innocent civilians and destroying monuments that are of great significance to Africa's heritage and civilization."

On Monday, Malian and French troops took control of Timbuktu, meeting with little resistance of the Islamists.