North Korea executed 80 people by firing squad in one day this month, a South Korean newspaper reported on Monday.
The public executions took place in seven cities on November 3, JoongAng Ilbo reported, quoting an unnamed source who was recently in North Korea.
Those executed had been accused of offences such as watching South Korean movies, prostitution and distribution of pornography.
In the eastern port city of Wonsan, about 10,000 people were made to watch the shootings in a stadium, the report said.
Reports of mass executions from North Korea are rare although numerous people who have fled the Stalinist country have said they were made to watch public executions, which the Government used as a deterrent.