Amnesty

In a statement, he said the government will prosecute those who fail to comply when the amnesty ends in February.

"Such malpractices constitute a very serious economic crime against the people of Zimbabwe," Mr Mnangagwa said.

Since taking office last week, he has pledged to crack down on corruption.

"Huge sums of money and other assets" have been "illegally externalised by certain individuals and corporates," the president said in a statement.

A new report by the human rights group alleges that mass hangings took place every week at Saydnaya prison between September 2011 and December 2015.

Amnesty says the alleged executions were authorised at the highest levels of the Syrian government.

The government has previously denied killing or mistreating detainees.

Activists say people are being detained without access to family or a lawyer, and held incommunicado without formal charges or a trial. They call it "enforced disappearances," and in the first five months of 2016 alone, a suspected 630 of these have already been documented, Amnesty says.

That amounts to an average of four or five people each day since 2015, according to the group. Half of these may never resurface.