SEOUL (Reuters) - North Korea said on Thursday (May 11) it was its sovereign right to "ruthlessly punish" American citizens it has detained for crimes against its government system, saying US media's description of such arrests as a bargaining ploy was "pure ignorance."

The North's KCNA news agency said the crimes of recent Americans detained by its authorities will soon be revealed.

Two American citizens affiliated with a private university in the North's capital have been detained in the past month.