A US citizen arrested in North Korea in October 2015 is awaiting charges of espionage against the secretive regime, it has been reported.

According to CNN, the man is a naturalised US citizen who identified himself as Kim Dong Chul, and is in a hotel in Pyongyang. It was claimed Kim had been working on the North Korean side of the inter-Korean special economic zone since 2001.

Kim also admitted that he spied on behalf of South Korea for nearly two years before being caught by North Korean authorities.

"I was tasked with taking photos of military secrets and "scandalous" scenes. They [South Korea] asked me to help destroy the [North Korean] system and spread propaganda against the government," he told CNN.

It is not uncommon for North Korea to detain foreigners over spying. Defectors and freed detainees have previously said foreigners are often under pressure from the regime to confess.

However US authorities are yet to confirm whether Kim is an American, although if true, he would be the only US prisoner being held the Pyongyang regime, which earlier released American nationals Kenneth Bae and Mathew Miller in November 2014.

Kim said he has a wife and two daughters in China but this also is yet to be corroborated.

The US State Department said: "Speaking publicly about specific purported cases of detained Americans can complicate our tireless efforts to secure their freedom."

It comes at a time of unease in the region, especially after Pyongyang claimed it had detonated a hydrogen bomb.

Earlier, the US had flew an advanced B-52 bomber over the Korean peninsula.