The US government banned imports of rough diamonds from Zimbabwe earlier this month over concerns that forced labour was being used in the African nation's mines.
Zimbabwe has dismissed the allegations. Secretary for Information Nick Mangwana says the US has no evidence of this, and that Washington has been "misinformed or misled".
The Marange mining region in the east of Zimbabwe is estimated to have one of the world's richest diamond reserves and is a vital revenue earner for a country in a dire economic straits.