Local media describe the blast at the stadium where the President of Zimbabwe was speaking as a "murder attempt"
In particular, while Emerson Mnangagua was delivering his campaign speech in a stadium, a loud explosion was heard near the official podium.
The president fled immediately, with a government spokesman saying he was safe and sound. State television reports that Vice President Kebo Mohadi suffered leg injuries, but it was not clear if his life was in danger.
The incident comes about five weeks before the July 30 election, which will be the first ballot in the era since the ouster of Robert Mugabe.
The cause of the explosion is still unclear.
The president did not suffer in the slightest, but the two vice presidents, Konstantino Chiwenga and Kebo Mohadi, a minister and several police officers were injured, according to government spokesman George Charaba.
"We are still waiting for information about what exactly happened," he added, explaining that the explosion took place at the official site. Three employees of the public television ZBC were also injured.
A French Agency correspondent who was monitoring the rally spoke of "many injured" who were taken to hospital but their condition has not been clarified so far.
"There was an explosion as Mnangagua left the stage and people started running in all directions. "Access to the podium (of the speakers) was banned but it seems that many of those who were there were injured", described the correspondent of the French Agency.
Mnangagua's main opponent in the election, Nelson Tsamisa, immediately condemned the "horrific events" in Bulawayo, a city considered a stronghold of the opposition. "We pray for the injured, we hope no one was killed. "Violence has no place in our political life," the Democratic Change Movement candidate wrote on Twitter.
"We pray for the lives and health of the injured. "At this difficult time, we must pray for peace in our country," said another opposition candidate, Pastor Yuan Maragwire.