A third day of talks over Zimbabwe's governance wound up on a conflicting note Tuesday amid reports that President Robert Mugabe and the leader of an opposition faction had reached a power-sharing agreement.

Shortly after the talks concluded, officials from Mugabe's party and the main opposition movement said the two sides had agreed on the plan, but a spokesman for the splinter group later denied the claim.

The reported agreement excludes Morgan Tsvangirai, the leader of the main Movement for Democratic Change. He won the first round of presidential elections in March but boycotted the runoff to protest widespread violence against opposition supporters.

Such an agreement would likely prompt protests from the West and some African governments for allowing the 84-year-old Mugabe to cling to his increasingly autocratic 28-year reign that has driven his once thriving nation to economic ruin.

South African President Thabo Mbeki, who mediated the talks, did not comment to reporters as the third day of talks concluded.

But Welshman Ncube, spokesman for the splinter faction of the Movement for Democratic Change, denied reports that his leader, Arthur Mutambara, had signed an accord with Mugabe.

"It's a lie," he said.

The officials from the ruling party and the main opposition movement led by Tsvangirai said that Mugabe and Mutambara both endorsed the plan. They spoke on condition of anonymity because mediator Mbeki has insisted on confidentiality.

Mutambara himself would not comment before Mbeki issued a statement.

Tsvangirai's faction has 100 seats in Parliament, just ahead of the Mugabe's ruling ZANU-PF's 99. Mutambara's faction holds only 10. He agreed to form a parliamentary alliance with Tsvangirai after the March elections, but if he now switches allegiances, it will give the majority to Mugabe's party. However, it is uncertain whether all his lawmakers will follow him into the ZANUA-PF fold.

Mugabe won the run-off of Zimbabwe's presidential elections after Tsvangirai boycotted it to protest widespread violence. Tsvangirai won the first round, though not by an outright majority.

Mugabe brushed off questions as he left the hotel in the capital Harare after three days of grueling talks, saying: "I'm sleepy."

But he denied that the negotiations had failed. "Talks will never collapse as long as we have tongues," he said.

The key stumbling block has been how much power Mugabe is willing to cede to the opposition movement.

Tsvangirai has said he could work with moderates from Mugabe's ZANU-PF party, but not with Mugabe.

ZANU-PF and powerful police and army generals of the Joint Operational Command insist Mugabe must remain president.

Mugabe and ZANU-PF have ruled Zimbabwe since the country gained independence in 1980. But his land reform policies that have laid waste to the country's once-thriving agricultural sector and he has resorted to repression to hold on to pwer.

Zimbabwe now has the world's highest rate of inflation, the majority of the population is unemployed and basic goods and food hard to find.

Human Rights Watch accused the ruling party and its allies of involvement in the killings of at least 163 people, and the beatings and torture of more than 5,000 others since the March elections.

The group said 32 opposition supporters have been killed since the June 27 runoff, and two since ZANU-PF and the opposition signed the memorandum of understanding that paved the way for negotiations on a power-sharing government.