Harare - Zimbabwe President Emmerson Mnangagwa said he suspected dissidents from his own party linked to Robert Mugabe's wife were behind an explosion at a rally he attended last week.
Two people died in the blast that rocked a stadium in Bulawayo as 75-year-old Mnangagwa left the podium.
Mnangagwa, who replaced Robert Mugabe in a bloodless coup in November, told the BBC he believed the attack had been carried out by the G40 group - a faction in the ruling Zanu-PF party which wanted Grace Mugabe to succeed her husband.
He did not accuse Grace Mugabe of being involved in the plan but said he expected arrests to be made soon.
"I don't know whether it was one individual, I would think it is broader than one person. I would think this is a political action by some aggrieved persons," Mnangagwa said.
During Mugabe's final months in office, the G40 faction accused Mnangagwa, who was then vice president, of plotting with the military to grab power.
Mugabe fired Mnangagwa as his deputy in November last year, but top army generals intervened days later, sent tanks into the streets, took over government buildings and eventually forced Mugabe to resign.
Mugabe later accused Mnangagwa of betrayal and said his presidency was illegal.