The political crisis in Zimbabwe is continuing to dominate a summit of southern African leaders as they try to push for a deal in Johannesburg. Zimbabwe's President Robert Mugabe and the main opposition leader, Morgan Tsvangirai, are at the talks. Mr Tsvangirai is said to have agreed in principle for Mr Mugabe to retain the title of president, while he takes on a beefed-up prime ministerial role. The key sticking points are reported to be over the exact balance of power. Mr Tsvangirai told reporters on Sunday morning that the negotiations were going "very well", Reuters reported. But in an interview with the New York Times, Mr Tsvangirai said the most basic issue of how he and Mr Mugabe would share power remained unsettled. And Mr Tsvangirai indicated that he would only be prepared to compromise so far. “It's better not to have a deal than to have a bad deal,” Mr Tsvangirai told the newspaper. Mr Tsvangirai finished ahead of Mr Mugabe in the first round of the presidential election in March and his Movement for Democratic Change (MDC) also won a majority in parliamentary elections. But Mr Tsvangirai pulled out of the second round of the presidential election, citing a campaign of violence against his supporters. Mr Mugabe won the vote unopposed. South Africa's Thabo Mbeki has been mediating long-running talks on how to address the political deadlock in Zimbabwe. The discussions have continued at this weekend's summit of leaders in the 14-member Southern African Development Community (Sadc). Mr Mugabe joined other regional leaders at the head table, while Mr Tsvangirai took a seat with other invited guests on the floor. Arthur Mutambara, head of a breakaway MDC faction, is also attending. Sticking points in the power-sharing talks are reported to include: • the balance of power between Mr Mugabe and Mr Tsvangirai • the make-up of any coalition cabinet • control of Zimbabwe's security forces • the possibility of an amnesty over post-election violence Pressure on Mbeki Some critics believe regional leaders' handling of the Zimbabwe crisis has reflected badly on them. Events in Zimbabwe were a "blot on the culture of democracy", Zambia said. The rare public criticism, attributed to Zambian President Levy Mwanawasa, comes after Botswana's president decided to boycott the summit in protest. Zambia's Foreign Minister Kabinga Pande said the "regrettable events" in Zimbabwe had "no doubt left a serious blot on the culture of democracy in our sub region. "Not only were these events alien to our region but they also brought into question Sadc as an institution capable of promoting the rule of law and democratic governance," he added, in a statement he read on behalf of President Mwanawasa, who is in hospital after suffering a stroke. Pressure has been mounting on Mr Mbeki to secure a deal - as evidenced by a noisy rally by trade unionists linked to Mr Mbeki's ruling party outside the summit convention hall in Johannesburg. Mr Mbeki has said he is determined to reach a deal and has promised to stay in Zimbabwe for six months to get one if necessary. Source: BBC