HARARE, Zimbabwe — Lawyers representing six diamond mining executives held in Zimbabwe asked a Harare court on Tuesday for their release, saying there were no criminal grounds for their detention.

The six executives, from two diamond-mining firms, were detained on suspicion of fraudulently obtaining a licence to mine gems in the controversial Marange fields.

"What we have is a very simple contractual matter," lawyer Lewis Uriri told the court in a bail application.

"The fraud charges would not stick," he said.

Among the executives are Dominic Mubaiwa, chief executive of government mining firm Zimbabwe Mining Development Corporation, and Lovemore Kurotwi, the local head of Canadile Miners, a joint Zimbabwe-South African venture.

The executives are accused of duping the government into believing that a non-existent South African firm was ready to invest two billion dollars in Zimbabwe in order to obtain a licence for Canadile Miners.

The court is due to give its ruling on the bail request on Wednesday.

Zimbabwe has contracted three firms -- South Africa's New Reclamation Group, China's Anjin and Canadile Miners -- to mine in the Marange fields, believed to be the cash-strapped country's largest diamond find in a decade.

Last week the Kimberley Process Certification Scheme (KPCS) met in Israel and failed to agree whether to allow Zimbabwe to sell gems from Marange.

Zimbabwe has said it will sell the diamonds with or without the Kimberley seal of approval.

By AFP