Angola's law enforcement authorities have deported since the beginning of 2009 more than 6,000 foreign nationals who were caught illegally digging for diamonds in the African country's northeastern region of Lunda Norte, Mining Weekly reported.

Angola's police chief Francisco da Cruz said in an interview with Angola's national radio that many of the illegal diamond diggers had crossed the border from the Congo in search of diamonds left in abandoned diamond mines.

Since the global financial crisis hit the diamond industry and the dramatic drop in demand for diamonds and jewelry, several diamond mining firms that have been operating in Angola have stopped their mining operations and abandoned the worksites.

Angola, the world's fifth largest diamond producer, only allows firms that partner with state-owned diamond company Endiama to explore for gems in the southwestern African nation.

"We have now identified the main areas where illegal diamond mining is taking place and have carried out several missions to discourage the practice," da Cruz said.