HARARE - A pan-African institute in Harare was burnt down on Tuesday, ahead of a planned press conference by opposition leaders.
They were to have briefed journalists about their rejection of the proposed extension of President Emmerson Mnangagwa's rule.
Zanu-PF announced last week that it plans to amend Zimbabwe's constitution to allow Mnangagwa to remain in power until 2030.
Professor Ibbo Mandaza, a founding trustee and chairperson of the Southern Africa Political Economy Series Trust, said it has always been a target.
Police arrested some young supporters of the coalition of opposition parties.
eNCA correspondent Pindai Dube reports.