Zimbabwe’s opposition says it has reached provisional agreement with the ruling party on a constitutional amendment that would pave the way for a unity government.

The two opposition officials says many other issues remain. Among them is the contentious division of Cabinet posts. The officials spoke on condition of anonymity because of a media blackout imposed by South African mediator Thabo Mbeki.

Zimbabwe’s negotiator did not answer his cell phone Friday.

The constitutional amendment would need to be passed by parliament to allow formation of a power-sharing government and creation of the post of prime minister for opposition leader Morgan Tsvangirai. Robert Mugabe would remain president.

The political deadlock has fueled the country’s worsening economic and humanitarian crisis.