Zimbabwe's President Robert Mugabe has agreed to share power with opposition leader Morgan Tsvangirai after more than two decades as the southern African country's dominant politician.

South African President Thabo Mbeki, who worked as a mediator between the two parties, did not immediately offer details but said Thursday an agreement would be signed and made public Monday. "I am absolutely certain that the leadership of Zimbabwe is committed to implementing these agreements," Mbeki said at a news conference late Thursday.

Tsvangirai announced the parties "have got a deal." There was no immediate statement from the 84-year-old Mugabe and no clear indication of how the two parties would share power.

The major issue has been how Mugabe and Tsvangirai would divide responsibilities and who would have the most power. Tsvangirai insisted on a leading role, while Mugabe appeared unwilling to surrender much of the authority he has wielded since the former rebel leader was elected president after the country won independence from Britain in 1980 following a 17-year war.

While Tsvangirai's MDC party won legislative elections held in March, the party did not win by a wide enough margin to take power. The MDC withdrew from the widely denounced run-off vote held in June, citing intimidation and violence against its supporters. Mugabe has been under increasing pressure to reach an agreement with Tsvangirai to end the political standoff.

Zimbabwe is facing severe economic problems, including inflation of more than 11 million per cent and chronic food and fuel shortages.

With files from the Associated Press