HARARE, Zimbabwe - Police banned all political rallies Friday as Zimbabwe's crisis deepened nearly two weeks after a presidential election that produced no official winner.

Opposition leader Morgan Tsvangirai says he won the vote outright and has been traveling the region to try to persuade neighboring leaders to pressure President Robert Mugabe to step down. Southern Africa's leaders are to meet in Zambia on Saturday to discuss the crisis.

"All political parties are warned against creating mayhem as we know there are many people who wish Zimbabwe to lose its peace," Senior Assistant Police Commissioner Faustino Mazango said. "Surely those who want to provoke a breach of peace, whoever they are and whatever office they hold, will be dealt with severely."

The opposition has accused security forces and ruling party militants of engaging in a wave of violence against perceived opponents since the vote and of clamping down on the opposition.

Opposition spokesman Nelson Chamisa said the Movement for Democratic Change party had planned a rally for Sunday.

"You can't be a political organization and not hold a rally, that is what makes us who we are, how we communicate with our supporters," he said, adding that they had not decided whether to go ahead with the rally.

The party leadership also would consider calling a general strike when it meets Sunday, he said.

"We cannot accept a declaration of a police state. People have just voted for change, for democracy and what do they get? This is unacceptable. This is ridiculous," he said.

Official results from the March 29 election have yet to be released. Independent observer tallies suggest Mugabe, the nation's ruler for the past 28 years, lost the vote, but that a runoff would be necessary because no candidate won the majority needed for outright victory.

"We know the results of the election," Tsvangirai said Friday. "We are tired of waiting. Not for some official announcement but for Mugabe to accept the result that he knows."

Tsvangirai met with South African President Thabo Mbeki on Thursday to press his case, opposition spokesman Nqobizitha Mlilo said.

"The meeting went well," Mlilo said. "We're cautiously optimistic about the outcome." Mbeki's spokesmen could not be reached for comment.

Mbeki has been the chief regional mediator in Zimbabwe's economic and political crisis, and other African leaders have deferred to his strategy of "quiet diplomacy." But that strategy has been criticized by some in the region and the West.

Zimbabwe state radio said the country would be represented at a regional summit Saturday by three senior ministers from its recently dissolved Cabinet. It did not say whether Mugabe himself would attend.

Tsvangirai appealed to the neighboring leaders "to ensure that democracy prevails in Zimbabwe."

"This is a historic moment for SADC and a defining moment for Africa. We can show the world that we, Africa, can solve our own problems and safeguard democracy and the rule of law," he said in a statement.