Zimbabwe's opposition says talks on forming a unity government are deadlocked but that negotiations could continue Friday.

An opposition spokesman, Nelson Chamisa, says the party is asking the mediator of the talks, former South African President Thabo Mbeki, to help find a creative way of breaking the deadlock.

President Robert Mugabe expressed optimism Thursday about a breakthrough, but said compromise is needed on all sides.

The talks in Harare involve Zimbabwe President Robert Mugabe, main opposition leader Morgan Tsvangirai and opposition faction leader Arthur Mutambara.

Tsvangirai threatened to pull out of a power-sharing deal Sunday, a day after Mr. Mugabe unilaterally assigned control of key ministries, including defense and foreign affairs, to his ZANU-PF party.

Thursday, Zimbabwe's state media said President Mugabe may alter the Cabinet lineup he announced last week in an effort to save the power-sharing deal.

Mr. Mbeki helped broker the original deal, meant to end the crisis stemming from Zimbabwe's disputed presidential elections.

The deal, reached in September, calls for ZANU-PF to control 15 ministries, with the two factions of the opposition Movement for Democratic Change getting 16. Mr. Mugabe would remain as president, with Tsvangirai becoming prime minister.

The sides are under pressure to reach a final deal so Zimbabwe can start to recover from its deep economic crisis. The country has 80 percent unemployment and an inflation rate officially estimated at 231 million percent.

Witnesses are reporting severe food shortages nationwide, especially in the south.

Some information for this report was provided by AFP, AP and Reuters.