Zimbabwe's political leaders were meeting with their southern African counterparts in Johannesburg Sunday for talks aimed at pulling the country's historic power-sharing agreement back from the brink of collapse, according to DPA. Zimbabwean President Robert Mugabe and Movement for Democratic Change (MDC) leader Morgan Tsvangirai are attending the extraordinary summit of the 15-nation Southern African Development Community (SADC), which was called to pressure the two men into forming a unity government. Opening the summit South African President Kgalema Motlanthe said it was "disappointing" that, two months after agreeing to share power, Mugabe's Zanu-PF party and the MDC could still not agree on its make-up and called on the leaders to show "political maturity." The conflict in the eastern Democratic Republic of Congo, is also on the agenda of the meeting, which five heads of state, including Congolese President Joseph Kabila, and senior officials from other SADC members are attending. Motlanthe, whose country holds the rotating SADC chair, backed calls for an immediate ceasefire to allow the delivery of humanitarian assistance to refugees displaced by the fighting and urged the parties to the conflict to pursue a political solution.