(CNN) -- The run-off for Zimbabwe's presidential election will be held June 27, Zimbabwe's Electoral Commission said Friday.
Morgan Tsvangirai won 47.9 percent of the presidential vote according to official results.
In the first round of voting March 29, opposition leader Morgan Tsvangirai of the Movement for Democratic Change (MDC), received more votes than President Robert Mugabe, but the electoral commission's official tally said Tsvangirai failed to win enough votes to avoid a runoff.
MDC disputed that, saying that Tsvangirai won 50.3 percent of the vote, giving him the necessary majority. The party argued that the election commission, which delayed publicly releasing the results for weeks, had fudged the numbers to protect Mugabe.
"My party, the Movement for Democratic Change, is a government-in-waiting that is not prepared to wait anymore," Tsvangirai told a political conference in Belfast, Northern Ireland, on Friday.
"We will pioneer a new form of democratic governance, taking our agenda directly to the people," he said. "After all, the MDC began as a people's party. Never again will we take something so precious as freedom for granted."
Since the balloting, the MDC and church groups have reported kidnappings, torture and other violence, including the deaths of 25 opposition party members. They say the violence targets opponents of Mugabe and his Zanu-PF party. Mugabe has ruled the southern African country since it became independent 28 years ago.
Amnesty International warned Thursday that the violence in Zimbabwe is reaching "crisis levels." The organization said large numbers of Zanu-PF supporters and war veterans are "assaulting perceived MDC supporters" in a district in Midlands province in central Zimbabwe and in another in a Mashonaland Central district, in the northern corner of the country.
The war veterans were "recruiting local youths to attack" people thought to be MDC supporters, Amnesty International said. "Police appear to be unwilling to stop the violence," the organization said, and they were "only acting to arrest MDC supporters suspected of carrying out attacks on perceived Zanu-PF supporters."
In addition to the 25 MDC supporters the opposition group says have been killed since the March election, church groups have reported the deaths of eight people at the hands of militias in an apparent crackdown on the opposition and its supporters.
Amnesty International put the death toll slightly lower, saying at least 22 people had been killed since the election. More than 900 have been injured, the organization said.
On Friday, Tsvangirai appeared confident that he will win the run-off. "We will triumph over the dictatorship of Robert Mugabe," he promised, calling on African countries to assist Zimbabwe in achieving a smooth transition of power.
Tsvangirai said Mugabe's government is motivated by greed and is unable to address issues plaguing Zimbabwe, including the economy, health care, and education.
The opposition leader promised his government would promote a policy of "inclusion and tolerance," and he said no Zimbabwean would have anything to fear from the new government.
"In Zimbabwe, we never stop hoping for a better tomorrow," he said. "Hope is our ammunition in the fight against terror. It is the fuel that drives us and the glue that binds us. I know that this hope is not misplaced."
CNN correspondent Nkepile Mabuse contributed to this report.