Zambian police stops Kaunda's son from leaving the country

Meanwhile, the authorities have confiscated the passports of Wezi Kaunda and his wife, Deirdre.

Wezi Kaunda said they were trying to cross the border into Zimbabwe to attend to family matters when immigration police stopped them.

He said an aide travelling with them also had his passport confiscated.

The Zambian authorities have said they confiscated Wezi Kaunda's passport in order to monitor him more closely.

From the newsroom of the BBC World Service