Former US President Jimmy Carter has reportedly arrived in North Korea to negotiate the release of a US citizen who has been detained since January.

Senior US officials told reporters that Carter was travelling to North Korea on a “purely humanitarian mission” to free 30-year-old Aijalon Mahli Gomes. Gomes, a devout Christian from Boston who taught English in South Korea, was arrested on January 25 and sentenced in April to eight years of hard labour for entering North Korea illegally and for an unspecified "hostile act".

Earlier this month, a team sent by the US State Department to visit North Korea tried to free Gomes but was not granted permission to do so.

North Korea has reportedly requested a visit by a high-profile US figure to gain the release of Gomes, and one US official told The Associated Press that North Korea had agreed to free Gomes if Carter came for him.

Foreign Policy magazine, which first broke the news of Carter’s trip, reported the former president as the top pick among several possible candidates to help secure Gomes’ release. Others who were reportedly considered included Senator John Kerry and New Mexico Governor Bill Richardson.

Last year, former US President Bill Clinton flew to Pyongyang to free two US journalists, Euna Lee and Laura Ling of Current TV, who were sentenced to prison after illegally entering North Korea.

At the time, North Korea similarly offered to release their detainees if Clinton came to negotiate their release. The two journalists were consequently freed.