An explosion rocked the White City stadium in Bulawayo where Mnangagwa addressed thousands of supporters earlier this afternoon. The blast occurred close to the VIP tent when Mnangagwa waved to supporters while leaving the podium.

Mr Mnangagwa said an object "exploded a few inches away from me - but it is not my time".

Video footage from White City Stadium shows an explosion happening close to Mr Mnangagwa as he was leaving the stage having addressed supporters.

This afternoon, as we were leaving a wonderful rally in Bulawayo, there was an explosion on the stage. Several people were affected by the blast, and I have already been to visit them in the hospital.

— President of Zimbabwe (@edmnangagwa) June 23, 2018

Both vice-presidents Constantino Chiwenga, his wife, Kembo Mohadi, a minister and journalists sustained injuries in the blast. Mnangagwa has visited a hospital to check on the injured.

The president was in Bulawayo, Zimbabwe's second city and an opposition stronghold, to campaign for his Zanu-PF party ahead of nationwide elections taking place on 30 July.

"People started running in all directions and then immediately the president's motorcade left at a very high speed," an AFP correspondent at the scene reported.

The Zimbabwean President took power in November 2017 after long time leader Robert Mugabe stepped down following a military intervention. The July the 30th vote is the first without Mugabe since independence in 1980.

In an interview broadcast after the explosion on national broadcaster ZBC, the president said he did not think those responsible came from Bulawayo. Mnangagwa said the injured included Vice President Kembo Mohadi, the wife of Vice President Constantino Chiwenga, the environment minister and the deputy speaker of parliament.

Several security personnel were also hurt, the state-owned Herald newspaper said. State television ZBC said 42 people were injured in the explosion, six of them seriously.

Mnangagwa also visited injured people in hospital alongside Chiwenga. Health Minister David Parirenyatwa said some of the injured had serious stomach wounds.