(CNN) -- Zimbabwean opposition leader Morgan Tsvangirai had harsh words for President Robert Mugabe on Sunday, as he stood near the casket of a man he says was killed by Mugabe's supporters.
Morgan Tsvangirai on Sunday address mourners at the funeral of activist Tonderai Ndira.
"This is a clear testimony of the callousness of this regime," Tsvangirai said to a funeral procession of hundreds gathered outside the capital city of Harare.
"They can kill us. They can maim us. But we are going on the 27th of June, our hearts dripping with blood, to vote him out of office."
Tsvangirai was referring to the date of the runoff election with Mugabe. On Sunday, Tsvangirai was at the funeral of Tonderai Ndira, a senior member of Tsvangirai's Movement for Democratic Change party who was kidnapped and shot to death, according to MDC party members. Watch Tsvangirai address mourners »
MDC members have accused Mugabe supporters of the attack, along with other election-related violence.
A Mugabe Cabinet member has denied that the government had any role in the killing, and said the report was an effort by the MDC to gain international sympathy.
The fallout from the controversial March 29 election has caused international concern. The Zimbabwe Electoral Commission, after a long delay, ruled that neither candidate won the required majority of votes, and scheduled a runoff election for June 27.
Tsvangirai, who claims he won the first election, wants international observers to monitor the second round of voting, but Mugabe's government has turned down the demand.
Since the March balloting, there have been numerous reports from the MDC and church groups about kidnappings, torture and other violence, including the deaths of 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.
CNN's Nkepile Mabuse contributed to this report.