JOHANNESBURG, South Africa (CNN) -- Zimbabwe opposition leader Morgan Tsvangirai will contest the presidential runoff with incumbent Robert Mugabe, he announced on Saturday.
The head of the Movement for Democratic Change made his declaration in the South African capital of Pretoria, ending speculation about his plans.
He said voters and supporters had told members of his party that they would support him in a second round of voting against Mugabe.
If Tsvangirai had not entered the runoff, Mugabe -- in power for nearly three decades -- would have retained the presidency by default.
"I am ready, the people are ready," Tsvangirai said, according to The Associated Press.
"I intend to return as shortly as possible and intend to begin a victory tour."
Tsvangirai has been away from Zimbabwe seeking support from other Africa leaders while the March 29 election results were delayed.
However, his supporters fear he may not be safe when he does come back, AP reported.
"They beat him up before and this may happen again, just to break him down," Fisher Murambatsvina, a 28-year-old MDC activist, told AP. "It's risky for Morgan Tsvangirai to come back. The army is in charge. Right now, I don't think he will be safe if he is coming to start his campaign."
Another supporter was doubtful that the runoff would be fair.
"How are we going to campaign in the runoff as MDC supporters?" Tapiwa Mudiwa told AP. "We can't wear MDC T-shirts. We fear we can't even go for rallies. Cars are being burned."
Zimbabwe's electoral commission finally announced last week that Tsvangirai won more votes than incumbent Robert Mugabe in the presidential race, but not enough to avoid a runoff.
The commission has yet to announce a date for the runoff, and Tsvangirai had previously insisted he would not announce his decision until that date was set.
Tsvangirai said staying out of the race would have betrayed the people's vote. He promised not to shy away from the opportunity to oust Mugabe, and said he was confident of a win.
By law, the electoral commission must announce a date for the runoff within 21 days of the announcement of results, but the ZEC chairman told CNN it would not be possible to have a vote within that timeframe.
MDC sources have told CNN that the commission is still trying to secure funding for the vote.
Tsvangirai said Saturday that missing the 21-day window as stipulated by law would damage the ZEC's credibility.
He also said election-related violence in Zimbabwe was increasing and that he knew it may escalate further leading up to the runoff, but he said the MDC would not take the chance of allowing Mugabe to remain in power.
The MDC initially refused to agree to a second round of voting, claiming Tsvangirai already had enough votes to replace Mugabe.
It said the initial tally of votes showed Tsvangirai garnered 50.3 percent, which would have averted a runoff. The electoral commission's official tally showed Tsvangirai won 47.9 percent compared with 43.2 percent for Mugabe.
Meanwhile, South African president Thabo Mbeki arrived in the Zimbabwe capital, Harare, Friday for more election crisis talks with the political leadership there, the South African Foreign Affairs Ministry said.
A ministry statement said only that Mbeki would be traveling in his capacity as head of the Southern African Development Community (SADC), which represents a dozen regional countries.
Mbeki dispatched a team earlier this week to look in to the violence in neighboring Zimbabwe. Mbeki's office did not give any details.
The opposition party has said 25 of its supporters have been killed since the vote, and this week, police arrested two journalists, a lawyer and a trade unionist.
Mbeki has sided with Mugabe on the election issue, saying it was not a crisis at their last meeting in Harare on April 12.
However, Tsvangirai has been critical of Mbeki's mediation role in Zimbabwe, calling for him to step aside.
The MDC leader said problems in Zimbabwe began long before the recent election and that Mbeki had been part of the mediation discussion for close to a decade.
"Well, it is nine years since the emergence of this Zimbabwean crisis. In any measure of success, I think nine years is too far, too long without a resolution in sight," Tsvangirai said.
"So I think that those who are making this criticism of the role played by President Mbeki, I think, are justified," he told CNN.