Zimbabwe's top opposition leader said Saturday he will take part in a presidential runoff against the country's longtime leader Robert Mugabe and will soon return to his homeland.

Morgan Tsvangirai, addressing reporters in South Africa, said his supporters would feel "betrayed" if he did not face Mugabe in the runoff.

"I am ready, the people are ready," he said. "I intend to return as shortly as possible and intend to begin a victory tour," he said.

Tsvangirai had said previously that he won the first round of elections outright and that official figures showing a second round was necessary were fraudulent.

Opposition officials and independent human rights activist have accused Mugabe of orchestrating violence against the opposition since the first round on March 29. The violence, and the need to try to rally support, have kept Tsvangirai and other top opposition figures out of Zimbabwe since the first round.

Observers inside and outside Zimbabwe have questioned whether a second round could be free and fair with the opposition unable to campaign freely because of attacks and threats.