HARARE, Zimbabwe - A third day of talks on Zimbabwe's governance wound up on a conflicting note Tuesday amid reports 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 against 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 power.

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

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

"It's a lie," he said.

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

Mutambara would not comment before Mbeki issued a statement.

Tsvangirai's faction has 100 seats in Parliament, just ahead of the Mugabe's 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 legislators would follow him into the ZANU-PF fold.

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

But he denied 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 governed Zimbabwe since the country gained independence in 1980.

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.