Updated

Zimbabwe's prime minister is suing President Robert Mugabe, alleging he violated the constitution and their power-sharing agreement.

Morgan Tsvangirai says Mugabe's unilateral appointment of 10 provincial governors last month was unconstitutional and he seeks annulment. In court papers filed Thursday, he says Mugabe violated the constitution intentionally. He says the power-sharing agreement requires the president to consult with the prime minister before making key appointments, and that Mugabe did not.

The presidency did not immediately comment.

The troubled coalition government was formed after disputed, violence-marred 2008 elections. But it is deeply divided, undermining its job of ushering in a new constitution and preparing for general elections.