The purpose of his visit to North Korea is unknown, but CNN said that the US State Department says he is not going to visit the North in any official US capacity.

It would be the fifth visit by Rodman since February 2013 when he first visited the North in what could be seen as "basketball diplomacy." He met with North Korean leader Kim Jong-un, who is known to be an avid basketball fan.

During his last trip in January 2014, he led a team of former NBA players in a goodwill game with a North Korean selection for Kim's birthday, which falls on Jan. 8.

North Korea's state media has yet to release a report on Rodman's visit. South Korea's unification ministry declined to comment.

His trip came amid mounting tensions between the US and the North over Pyongyang's pursuit of nuclear and missile programs. North Korea is developing its nuclear weapons and missiles at an alarming pace with the stated goal of launching an intercontinental ballistic missile capable of hitting the US mainland.

The US is stepping up efforts to muster international support for further pressure on North Korea over its provocative acts.

Pyongyang also currently has four Americans detained including Kim Dong-chul, a 62-year-old Korean-American, and Otto Warmbier, a US college student.

During his 2014 trip to the North, Rodman made remarks that appeared to blame Kenneth Bae, a Korean-American man who was held in captivity in North Korea from 2012-2014, for his detention. Bae was sentenced to 15 years of hard labor for unspecified anti-state crimes.

His comments drew criticism at that time, but Bae said in his interview with CNN in 2016 that he is grateful to Rodman for being a "catalyst" for his release from the repressive regime. (Yonhap)