President Robert Mugabe\'s plan to call an election in Zimbabwe unilaterally for March 2012 would be \"illegal\", and the vote cannot be held until reforms are carried out to make it fair, Prime Minister Morgan Tsvangirai said on Saturday, according to Reuters. Mugabe and Tsvangirai, longstanding foes, are in an uneasy power-sharing coalition set up two years ago following disputed 2008 elections. Last week, Mugabe accused Tsvangirai\'s Movement for Democratic Change of stalling constitutional reforms in order to delay the vote, which Mugabe had wanted in 2011. The veteran ruler vowed to call for elections whether the MDC agreed or not. Tsvangirai told thousands of MDC supporters at a rally in Harare that the president did not have the authority to set a date unilaterally. \"Mugabe says he wants an election in March. That\'s illegal, we both have to agree on the date for the next election,\" Tsvangirai said. He said the MDC would insist first on an agreement with Mugabe on electoral reforms and the involvement of the regional Southern African Development Community (SADC) bloc, the African Union and the United Nations. The reforms would include a new voters\' roll and constituency boundaries as well as the removal of election officials who ran previous disputed polls, he said. \"SADC has said these are the steps which must be taken first. We want an election conducted in a free and fair environment, so there are no future disputes,\" Tsvangirai said. \"SADC knows that without a roadmap with clear timelines, we could have another disputed election.\" Tsvangirai said while the unity government had managed to arrest Zimbabwe\'s economic decline, sharp differences remained over policies such as a law championed by Mugabe which seeks to transfer control of foreign-owned firms to locals. \"The inclusive government cannot create jobs because of conflict of policy. Today, Mugabe assures investors that their investments are safe, but the next day (Empowerment Minister Saviour) Kasukuwere threatens to close down mines,\" Tsvangirai said. \"We\'re not in agreement with these policies. When we win the election, we\'ll adjust them so we restore investor confidence in our country.\"