A Stalin era mass grave has been uncovered in the Mongolian capital, Ulan Bator.

Investigators say the grave, found on a construction site, contains the bodies of hundreds of executed Buddhist monks and civilians.

They say that 348 skulls with bullet holes in the back have been found, and that the number of bodies could top 1,000.

Some 90 percent of the dead were found with the remains of yellow and red garments and religious items usually worn by Buddhist monks, investigators said. But objects belonging to civilians from the upper and middle classes were also found.

Historians say at least 30,000 intellectuals, dissidents, noblemen and monks were killed in purges by the Mongolian People's Revolutionary Party (MPRP) in the 1930s.

More than 700 monasteries and Buddhist temples were destroyed in Mongolia, which became the world's second Communist state in 1921 under the domination of the neighbouring Soviet Union.