N. Korea's Kim Jong-un 'executes' engineers blamed for apartment collapse

North Korean supreme leader Kim Jong-un has reportedly executed 500 people, including engineers, who worked on an apartment block that collapsed last week.

The 23-storey building went down in the capital Pyongyang, triggering a rare public apology from the North Korean regime.

According to news.com.au, Kim was reportedly unable to sleep after hearing about the collapse of the newly built block.

The building was reportedly meant to be home to top intelligence and police officials, as well as a large number of the ruling party elite.

Four engineers behind the construction were killed by firing squad on Kim's orders. A military official in charge of the project was sent to a prison camp.

While the secretive state has given no reason for the collapse, it is likely due to bad workmanship.