Zimbabwe's two vice presidents and dozens of others were injured in a blast at a political rally that president Emmerson Mnangagwa, who emerged unscathed by the explosion, said targeted him.
At least 41 were injured, including the two senior politicians, and were treated at three hospitals across the country, Health Minister David Parirenyatwa told a Sunday paper.
Footage circulating on social media showed an explosion and plumes of smoke around the president as he descended stairs from the podium at the city's White City stadium on Saturday.
Mr Mnangagwa said he was the target of the attack, which also injured Vice-Presidents Kembo Mohadi and Constantino Chiwenga.
The device "exploded a few inches away from me - but it is not my time", the president told the state broadcaster on Saturday night.
"These are my mortal enemies and the attempts have been so many.
"It's not the first attempt on my life. I'm used to it. Six times my office has been broken into. Cyanide was put in my offices so many times. I will continue."
The health minister said some of those wounded had lost limbs and some would require "serious surgery", and suggested that the number of injured could rise.
"We have no fatalities so far," Mr Parirenyatwa said.
Mr Mnangagwa, who was quickly rushed away from the scene of the explosion, later visited the injured in hospital.
The president appealed for calm after the blast saying peace was the best response to violence.
Apresidential spokesman ruled out a state of emergency.
George Charamba told the state-run Sunday Mail newspaper that the historic July 30 election would go ahead as planned.
While Bulawayo has long been a bastion of opposition to the ruling ZANU-PF and it was Mr Mnangagwa's first rally in the city, commentators suggest the attack could have been instigated by ructions within the ruling party. No arrests have been reported.
The polls in five weeks will be the first since Zimbabwe's veteran leader Robert Mugabe resigned following a brief military takeover in November last year after 37 years in power.
The intervention by the army was led by Mr Chiwenga who was then head of the armed forces.
The vote will be a key test for Mr Mnangagwa, 75, who succeeded the 94-year-old autocrat and remains untested at the ballot box.
He has pledged to hold free and fair elections as he seeks to mend international relations and have sanctions against Zimbabwe dropped.
Previous elections in Zimbabwe have been marred by electoral fraud, intimidation and violence, including the killing of scores of opposition supporters in 2008.
The EU appointed observers for the first monitoring of an election in Zimbabwe in 16 years.
Meanwhile, the death toll from an unconnected grenade attack at a rally for Ethiopia’s prime minister Abiy Ahmed climbed to two, a cabinet minister said, as police announced arrests over the blast.
"I'm so sorry to learn that we have lost another Ethiopian victim of yesterday's attack," Health Minister Amir Aman tweeted.
The blast occurred in a packed public square as Ethiopia's new prime minister was wrapping up a speech before tens of thousands of people.
The ensuing chaos injured more than 150 people and marred an event meant to build public support for Mr Abiy's ambitious reform agenda.
State-run Ethiopian News Agency reported police had arrested six people suspected of involvement in the blast, but gave few details.
Event organiser Seyoum Teshome on Saturday told AFP police grappled with someone attempting to hurl a grenade at the prime minister as he concluded his speech.
The explosive detonated amid the scuffle, though most of the injuries were caused in the ensuing panic, he said.
No group has publicly claimed responsibility for the attack, a rare instance of violence in the heavily policed capital.
Mr Abiy took office in April after years of anti-government unrest that pushed his predecessor to resign and the government to declare a nationwide state of emergency.
He has since announced plans to liberalise the economy and reconcile with neighbouring arch-enemy Eritrea.
Mr Abiy also lifted the state of emergency and released scores of jailed dissidents.
Ethiopia is completely controlled by the secretive Ethiopia People's Revolutionary Democratic Front and it is unclear how much support Mr Abiy has within the party.