The 21-year-old college student was arrested in January 2 as he was preparing to leave the country at the end of a tour.

As Yahoo News reports, Warmbier was arrested in late January after the North Korean government accused him of committing an "anti-state crime with tacit connivance of the USA government and under its manipulation".

Pyongyang has not said what possible punishment Warmbier may face.

The US state department strongly advises Americans against travelling to North Korea, which sometimes uses the detention of foreigners as a means of exerting pressure on its adversaries.

North Korea allowed the world to get its first glimpse of Warmbier, a student at the University of Virginia, two months after his arrest.

On Jan. 22, North Korea announced Warmbier had been arrested for "hostile acts".

Former president Bill Clinton went to Pyongyang to secure the release of journalists Laura Ling and Euna Lee in 2009, while Jimmy Carter traveled to the North Korean capital the following year to collect Aijalon Gomes, a Boston man who entered the country illegally.

The official also said the OH church member promised Warmbier a $10,000 used vehicle if the mission was successful.

The Korean government says the student was manipulated by a supposed member of an OH church, a secret university society and even the Central Intelligence Agency.

Russia concerned by N.Korea's readiness to use nuclear arms
Later, the impoverished country initiated a banned long-range missile test that successfully inserted an object into orbit. It's not clear how real that threat is.

Warmbier grew up in Wyoming, Ohio, northeast of Cincinnati.

According to KCNA, Warmbier said he was encouraged in his act by a member of the Z Society, an elite philanthropic organization that he hoped to join at the university.

Warmbier said he accepted the offer of money because his family is "suffering from very severe financial difficulties".

At the time, North Korea said the U.S. government had "tolerated and manipulated" him. The State Department warns against travel to the North.

Cultural understanding is always a win, say major tour operators, including Uri Tours, Young Pioneer Tours ("going where your mother would rather you stayed away"), and Koryo Tours.

According to KCNA, the slogan removed by Warmbier was aimed at inspiring "the Korean people's love for their system".

Pyongyang has in the past used detained USA citizens to extract high-profile visits from the United States, with which it has no formal diplomatic relations.

It took a visit in November 2014 by US spy chief James Clapper to bring home Matthew Miller, who had ripped up his visa when entering the country, and Korean-American missionary Kenneth Bae, who had been incarcerated since November 2012.

Numerous Westerners have been detained for allegedly leaving Bibles or other Christian materials behind: Jeffrey Fowle, for example, was kept six months for leaving scripture in the northeast city of Chongjin.