SEOUL • North Korea yesterday said it has detained an American university student for committing a "hostile act" and wanting to "destroy the country's unity", the third Western citizen known to be held in the isolated state.

The North's official KCNA news agency said Mr Otto Frederick Warmbier entered the country as a tourist and "was caught committing a hostile act against the state", which it said was "tolerated and manipulated by the US government".

Mr Gareth Johnson of the China- based Young Pioneer Tours said Mr Warmbier, a 21-year-old student at the University of Virginia, was on one of its North Korea tours and detained on Jan 2.

"We are in touch with Otto's family, the US State Department and the Embassy of Sweden in Pyongyang and doing all we can to secure his release," said Mr Johnson. The Swedish Embassy represents US interests in North Korea.

KCNA said Mr Warmbier had entered North Korea with an "aim to destroy the country's unity".

According to his social media profiles, Mr Warmbier is from Cincinnati, and an Echols Scholar, awarded to the top 7 per cent of incoming first-year students at the University of Virginia, where he majors in economics with a minor in global sustainability.

He has visited countries including Cuba, Ireland and Israel, according to his Facebook profile.

Mr Warmbier was detained four days before North Korea held its fourth nuclear test in violation of United Nations sanctions, drawing condemnation from its neighbours and the United States.

North Korea has a long history of detaining foreigners.

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

A South Korean-born Canadian pastor was arrested last year and given a life sentence for subversion. Earlier this month, a Korean- American man told CNN in Pyongyang that he was being held by the state for spying.

In 2014, Pyongyang freed three detained Americans. Last October, it released a South Korean national with a US green card after holding him for six months.

REUTERS