Johannesburg  - The suffering of Zimbabweans looked set to continue for some time to come Sunday after a summit of Southern African leaders tried but failed to breathe life into Harare's floundering power-sharing agreement.

After more than nine hours of talks among leaders of the 15-nation Southern African Development Community (SADC), Zimbabwean President Robert Mugabe and prime minister-designate Morgan Tsvangirai remained far apart on how to divide power.

Tsvangirai rejected SADC's proposal to break the deadlock, which involved his and Mugabe's parties sharing control of the hotly disputed Home Affairs Ministry, which controls the police and the electoral processes.

In a "poisoned" atmosphere like that between his Movement for Democratic Change (MDC) and Mugabe's Zanu-PF, "quite clearly the concept of co-ministering cannot work," Tsvangirai said.

Under the terms of the September 15 agreement brokered by South African ex-president Thabo Mbeki to worldwide acclaim, Mugabe remains president and Tsvangirai becomes prime minister of a unity government of 31 ministries.

Mugabe's Zanu-PF gets 15 ministries and the MDC 16 - 13 for Tsvangirai's party and 3 for a breakaway MDC faction led by Arthur Mutambara.

Two months later, the talks have foundered mainly on which party gets which portfolio.

The MDC has accused Zanu-PF of keeping all the most important portfolios for itself and of not being sincere about powersharing.

Opening the summit, South African President Kgalema Motlanthe, chairman of SADC, said the Zimbabwe impasse, which is framed by a worsening humanitarian crisis, was "disappointing" and called on the leaders to show "political maturity."

The summit also addressed the conflict in the eastern part of the Democratic Republic of Congo in the presence of Congolese President Joseph Kabila and senior officials from neighbouring Angola.

Blaming the "intransigence" of Congolese rebel leader Laurent Nkunda for the breakdown of past regional peace agreements, SADC Executive Secretary Tomaz Salamao, reading from a communique, said that SADC "would not stand by and witness incessant and destructive acts of violence by any armed groups, against innocent people of DRC."

"DRC Armed Forces need to be assisted in order to protect the territorial integrity and sovereignty of the country," SADC said, resolving to provided that aid and to send peacekeepers to oversee a ceasefire "if and when necessary" in Congo's North Kivu province.

Angola and SADC denied reports that Angolan troops were engaged in the Congo conflict on behalf of the national army.

"But if required they will be on the ground soon, subject to the report (on the situation) ... made by the military experts (from SADC)," Salamao said.

Sunday's emergency summit was the third SADC meeting this year to be taken up with the fate of Zimbabwe, a once model African economy that has been run into the ground by Mugabe's populist policies.

A warning by South Africa that it would take a hard stance this time had kindled some hope that regional leaders were about to break with tradition and get tough with die-hard Mugabe, who has ruled for 28 years. Instead, the summit backed his position.

Some 3 million Zimbabweans, about one quarter of the population, now require food aid, but Western donors, already under pressure to turn around their own economies, have been loathe to plough money into Zimbabwe until Mugabe's powers have been heavily curtailed.

Mugabe clung to power this year through two election defeats. The MDC won parliamentary elections in March, and Tsvangirai took more votes than Mugabe in a first-round presidential election. Mugabe won the second round of the presidential election, but only after Tsvangirai withdrew in protest over a state-sponsored killing spree against scores of his supporters.

Despite rejecting the "co-ministering proposal," Tsvangirai said Sunday that the MDC was still committed to power-sharing, subject to passage of a constitutional amendment that will, among other things, clarify division of powers between himself and Mugabe.

In particular, the party is concerned that Tsvangirai might not have the power to hire and fire ministers.

Arthur Mutambara, leader of an offshoot MDC faction that is also a party to the unity deal, sided with Mugabe and SADC over the Home Affairs Ministry.

"This agreement is as good as it gets," Mutambara said. (dpa)