Unnamed sources in Zimbabwe's MDC opposition say historic talks with the governing Zanu-PF party are deadlocked. A dispute has apparently arisen over a push by President Robert Mugabe's party to have MDC leader Morgan Tsvangirai appointed "third vice-president". The MDC sources said this was "insulting", and reflected negatively on the talks' facilitator, President Thabo Mbeki of South Africa. Talks began last week after a rare meeting between the two leaders. The delicate negotiations following this year's disputed elections are meant to be happening under a news blackout, but sources in the Tsvangirai camp have told the BBC that they have now ground to a halt. 'Lacks sincerity' The Associated Press news agency reported that Mr Mugabe's negotiators were to fly home to Zimbabwe on Monday, although it is unclear whether the talks are in recess or have broken down completely. AP quoted a different official in Zimbabwe saying Justice Minister Patrick Chinamasa and Social Welfare Minister Nicholas Goche - Mr Mugabe's negotiators - might be going home to consult the president about their mandate. The same official said Mr Tsvangirai had left Zimbabwe on Monday and was travelling to the South African capital, Pretoria, to consult his own negotiators. A source quoted by the AFP news agency said the proposal to name Mr Tsvangirai third vice-president showed a "complete lack of sincerity and the need to really address the issues and problems Zimbabwe is facing". Zimbabwe's current first and second vice-presidents are both high-ranking Zanu-PF members. A spokesman for President Mbeki told the BBC he had no knowledge of the talks breaking down. The South African government earlier criticised new sanctions imposed on Zimbabwe by America and the EU, saying they could obstruct the talks. Mr Tsvangirai pushed Mr Mugabe into second place in the first round of voting on 29 March but he pulled out of a 27 June run-off election after a wave of deadly attacks against his supporters. Source: BBC