Zimbabwean President Emmerson Mnangagwa on Tuesday vowed that elections next month would take place peacefully, defying the unexplained weekend blast that narrowly missed him but killed two bodyguards.
The president, who has claimed he was the target of the attack, said the blast was "calculated to achieve a bloodbath" and "destabilise the ongoing electoral programme".
Footage of Saturday's incident, which medical officials said killed two people and injured 49, showed a device exploding and smoke engulfing Mnangagwa.
Both vice presidents were slightly injured in the blast, as were several other top officials in the ruling ZANU-PF party.
Mnangagwa had just descended from the podium after addressing supporters at the White City stadium in Bulawayo, Zimbabwe's second largest city.
It is not known who carried out the attack, and there has been no claim of responsibility.
"Those merchants of terror must never be allowed to succeed, let alone stop the march of democracy, economic recovery and national progress which our people deserve," he said in a statement.
The first parliamentary and presidential polls of the post-Mugabe era are scheduled to take place on July 30.
Mnangagwa said the government was taking "comprehensive" security measures ahead of the polls, in which 23 candidates are contesting the presidency.
It is the largest field of presidential hopefuls in Zimbabwean history.
National politics were dominated by Robert Mugabe until he resigned last November following a brief military takeover after 37 years in charge.
Seventeen presidential candidates inked a peace pledge ahead of the vote while the leading candidates, Mnangagwa and the main opposition Movement for Democratic Change's leader Nelson Chamisa, sent representatives to the signing.
"Peaceful elections are a key ingredient for long-term peace and development in the country," said Selo Nare, chairman of the country's national peace and reconciliation commission which organised Tuesday's ceremony.
"The signing of the peace pledge is a demonstration of the political parties' commitment to enforcing the code of conduct which is now law."
Philippe Van Damme, the ambassador of the European Union (EU), which is deploying election observers to Zimbabwe for the first time in 16 years, welcomed the signing.
"We now have a powerful tool at hand to monitor electoral behaviour," he said in a statement.
Dozens of people were injured in Saturday's blast, which also killed two bodyguards