Zimbabwe's opposition leader Morgan Tsvangirai and President Robert Mugabe have reached a deal to share power. After mediating four days of talks in Harare, South African President Thabo Mbeki said the agreement would be signed and made public on Monday. Mr Tsvangirai has confirmed the deal, but Mr Mugabe has yet to comment. The government and the opposition MDC had already agreed that Mr Tsvangirai would be prime minister with Mr Mugabe staying on as president. Negotiations have been on-off since the end of July, but have stalled over the allocation of executive power between Mr Mugabe and Mr Tsvangirai, bitter rivals for a decade. 'Parallel governments' Mr Tsvangirai, leader of the Movement for Democratic Change (MDC), was first to announce the breakthrough, telling reporters simply: "We've got a deal." Later, Mr Mbeki told a news conference the two sides had agreed unanimously to form an inclusive government. He said: "I am absolutely certain that the leadership of Zimbabwe is committed to implementing these agreements." MDC spokesman Nelson Chamisa told the BBC: "Both political parties are committed, it's our wish that the deal will be successful." Zimbabwe's envoy to the UN, Boniface Chidyausiku told the BBC that the deal was a "triumph for African diplomacy". The UN special representative on Zimbabwe, Haile Menkerios, said the announcement marked a way forward that all sides could live with. Britain's Foreign Office said it was following the situation closely, adding that "our concern is the welfare of the Zimbabwean people". The discussions are thought to have been deadlocked over how many ministries each party should have in a unity government, and how much power Mr Mugabe should retain. Mr Tsvangirai has consistently demanded that he should become executive prime minister, thereby taking over some of the powers that Mr Mugabe has exercised for more than 28 years, the BBC's Peter Biles says. Mr Tsvangirai may now chair a new council of ministers and control the day-to-day running of the country, but Mr Mugabe will head the cabinet, our correspondent says. However, how two - in effect - parallel governments will work is unclear, he adds. Aid hopes The agreement opens the way for international donors to help to revive Zimbabwe's economy, the BBC Africa editor Martin Plaut says. It is now the fastest shrinking in the world with inflation galloping to more than 11m%. Mr Mugabe, in power since independence from Britain in 1980, won a controversial June presidential run-off election unopposed after Mr Tsvangirai withdrew, claiming the MDC was the target of state-sponsored violence. In the first presidential election in March, Mr Tsvangirai gained more votes than Mr Mugabe, but official results say he did not pass the 50% threshold for outright victory. Earlier on Thursday, British Prime Minister Gordon Brown said any power-sharing deal in Zimbabwe would be judged by how much it reflected legitimate election results. Source: BBC