About 300 Zimbabwean travellers blocked their government's security officers from arresting prominent opposition politician Tendai Biti at the border with Zambia, according to a document circulating on social media that appears to have been drafted by Zambia's Criminal Investigation Department (CID).

The document states that Zambian officials then intervened and threatened to arrest the Zimbabwean officers for "executing their mandate on Zambian soil".

A team of Zambian paratroopers, armed with AK-47 rifles, later arrived at the Chirundu border post and took Mr Biti away, the document says.

Zambia's Foreign Minister Joe Malanji told the BBC Mr Biti's asylum request has been turned down.

Mr Biti fled to Zambia after Zimbabwean police issued an arrest warrant for him, accusing him of "unlawfully" announcing that his party's leader, Nelson Chamisa, defeated President Emmerson Mnangagwa in last Monday's presidential election.

He is also accused of inciting the violence last Wednesday when MDC Alliance supporters clashed with security forces, leaving six people dead.

The MDC denies causing violence, and accuses the security forces of brutally cracking down on its leaders and activists.