Uganda police are investigating after a marijuana plantation was uncovered in the garden of a convent.

A regional police chief told the BBC that plants covering one acre had been found and uprooted in the southern Masaka district.

Two nuns and two porters have been questioned.

One of the nuns has been quoted by local media as saying the marijuana was used to treat farm animals, such as pigs.

Southern regional commander Emmanuel Muhuirwe told the BBC News website that only the porters had been arrested - not the nuns.

He said the nuns had been questioned because the garden was part of the convent.

But he said no-one had been charged yet and the porters have been released on bail.

Commander Muhuirwe also dismissed reports in Uganda's New Vision newspaper that the nuns had been angry that the police had entered the convent without permission, pointing out that the garden was separate from the convent building.