A Zimbabwean politician has been attacked in the capital, Harare, during the last day of campaigning before a referendum on a new constitution.

Sten Zvorwadza, who hopes to become the next Movement for Democratic Change MP for the city's Mbare suburb, was punched as he tried to put up posters.

The BBC's Andrew Harding witnessed the incident and said the youths also threw punches at him and his film crew.