Zimbabwe's President Emmerson Mnangagwa said he was the target of the attack which injured dozens of people
The blast that rocked a ruling party campaign rally in which Zimbabwean President Emmerson Mnangagwa narrowly escaped unharmed, has plunged the country into uncharted waters a month before the first elections in the post-Robert Mugabe era.
But authorities on Sunday ruled out delaying the polls as police said 49 rallygoers, including the country's two vice presidents, were injured in the attack, some of them seriously.
Mnangagwa has called for calm after the blast which went off "inches" away from him.
Footage circulating on social media showed an explosion and plumes of smoke around the president as he walked down stairs from the podium at the city's White City stadium in the second largest city of Bulawayo.
Mnangagwa said he was the target of the attack, which also injured Vice-Presidents Kembo Mohadi and Constantino Chiwenga, and which the state media is describing as an assassination attempt.
The device "exploded a few inches away from me", the president told state broadcaster on Saturday night, blaming the attack on his "mortal enemies".
"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."
The polls in five weeks will be the first since Zimbabwe's veteran leader Mugabe resigned following a brief military takeover in November last year after 37 years in power.
While investigations are under way, the government has ruled out a delay in the July 30 elections.
"As for the elections being postponed, a state of emergency being declared (due to the Bulawayo attack)... rest assured that the electoral programme proceeds as scheduled," the presidential spokesman George Charamba told the state-run Sunday Mail.
Police spokeswoman Charity Charamba on Sunday told reporters that "comprehensive investigations are in progress".
The upcoming election will be Mnangagwa's first at the ballot box.
- 'People must unite' -
In a voice note he released to the state media on Sunday, Mnangagwa called for unity and peace.
"In November (when Mugabe was removed) we all came together motivated by a dream, (for) a free, democratic and prosperous Zimbabwe, a peaceful Zimbabwe," he said, adding "now some people are trying to kill our dream".
"While we have all chosen the path of peace others unfortunately still cling to the tools of violence. I assure you they will not succeed," said the president.
"We as a people must unite."
Previous elections in Zimbabwe had been marred by electoral fraud, intimidation and violence, including the killing of scores of opposition supporters in 2008.
But never had there been explosives detonated at rallies or targeted directly at any political leaders.
Mnangagwa has pledged to hold free and fair elections as he seeks to mend international relations and have sanctions against Zimbabwe dropped.
- 'Internal crisis in ZANU-PF'-
While Bulawayo has long been a bastion of opposition to the ZANU-PF and it was Mnangagwa's first rally in the city, commentators suggest the attack could have been instigated by internal ructions within the ruling party.
"It looks very much like an internal crisis within ZANU-PF," said Gideon Chitanga of the Johannesburg based think tank Political Economy Southern Africa. "The end game in ZANU-PF succession politics will be long and it's ramifications dire".
Yet others point to the old grievances linked to the 1982-87 Gukurahundi crackdown which was widely seen as an effort by then-prime minister Mugabe to vanquish his ally-turned-foe, the ethnic Ndebele liberation leader Joshua Nkomo.
"The main uncertainties now are whether the reaction to the attack includes a crackdown on dissent and political rivals in the name of security or a delay in the election," said Hasnain Malik of the London-based Exotix Capital.
But for ordinary voters like Harare-based Crispen Pfundirwa, the main concern is that security is not tight in the run-up to the election.
"Since 1980 we have not seen any bomb blast at a rally. These sort of things don't happen in Zimbabwe but in Iraqi and Iran," said Pfundirwa.