Zimbabwe's security forces sealed the country's major cities without notice amid claims of plots to topple President Emmerson Mnangagwa's government.

Government buses - the only mode of public transport allowed under a lockdown to stop the spread of Covid-19- were being forced to drop off passengers at the check points.

The government has issued conflicting statements on the heightened security clampdown, but President Mnangagwa's spokesman George Charamba said it was meant to stop an uprising.

Unions representing other government workers also threatened to roll out protests in the coming days.

President Mnangagwa's government is under increasing pressure to deal with a worsening economic situation characterised by raging inflation.