Zimbabwe’s president has been left unscathed by an explosion at a campaign rally that state media said was an attempt to assassinate him.

He later visited his two injured vice presidents and declared the “cowardly act” will not disrupt elections.

Footage showed a smiling President Emmerson Mnangagwa walking off the stage and into a crowded tent where the blast occurred seconds later, sending up smoke as people screamed and ran for cover.

Officials said Mr Mnangagwa was whisked from the stadium rally to a nearby government building in Bulawayo, a traditional opposition stronghold.

The explosion went off a “few inches away from me, but it is not my time”, the president told state broadcaster ZBC.

Mr Mnangagwa, who has joked about multiple attempts on his life, said he was used to them by now.

At least eight people were injured, the state-run Herald newspaper said. Vice President Kembo Mohadi had leg injuries, while Constantino Chiwenga, a second vice president and the former military commander, had facial bruises, it said.

Most of the injured were discharged from a hospital after treatment, presidential spokesman George Charamba told the newspaper.

The blast and lack of clarity about who was behind it injected new uncertainty into preparations for the July 30 elections, the first since longtime leader Robert Mugabe stepped down in November after a military takeover.

Mr Mnangagwa, who was fired as Mugabe’s deputy in a ruling party feud shortly before the transition, took over with pledges to deliver free and fair elections.

He said he was awaiting further information about the blast but added those responsible must have come from “outside Bulawayo”. He added: “I can assure you these are my normal enemies.”

Mr Mnangagwa on Saturday evening appealed to the southern African nation for unity.

“The campaign has been conducted in a free and peaceful environment, and we will not allow this cowardly act to get in our way as we move towards elections,” he said.

Zimbabwe’s main opposition leader, Nelson Chamisa, said: “Our prayers go out to the injured and we hope no lives have been lost. Violence must have no place in our politics. ”

The United States and Britain were among countries that condemned the explosion. The US Embassy said “political violence in any form is unacceptable” and contrary to the progress needed to move Zimbabwe forward to “take its place on the global stage.”

Zimbabwe’s election next month will be the first without Mugabe since independence from white minority rule in 1980.

Mr Mnangagwa, a former justice and defence minister who served for decades as Mugabe’s enforcer, has invited Western election observers for the first time in almost two decades.

Past votes have been marked by violence and fraud, and the United States and others have said a credible vote is key to lifting international sanctions.