At least 37 gold miners died and many others were injured in the Central African Republic when a pit in which they were working collapsed after heavy rains, the country's presidency said.

The incident happened on Sunday at a gold mine in Ndassima, some 273 miles east of the capital, Bangui, and three days of national mourning have been declared.

"The toll of 37 is provisional as there were many injured," said Prosper Ndouba, spokesman for the president's office.

Ndouba said that 10 injured miners had been rescued but there were an unknown number of bodies still buried after the accident.

CAR, a former French colony, is rich in gold and diamonds but the country has endured decades of instability, with rebels sweeping from the north of the country to topple the president in March.