North Korea state media confirms arrest of US professor

North Korea on Wednesday confirmed the arrest of a US citizen who was lecturing in Pyongyang - the third American held in the country amid growing tensions with Washington.

US citizens Otto Warmbier on March 16, 2016, left, and Kim Sang-duk on April 29, 2016 are escorted at court in Pyongyang, North Korea. Source: AAP

Kim Sang-duk, or Tony Kim, was detained at the capital's airport on  April 22, as he tried to leave the country after teaching for several weeks at an elite university. 

In the North's first confirmation of the professor's detention, the official Korean Central News Agency (KCNA) said he had been held for "committing criminal acts of hostility aimed to overturn the DPRK", using the country's official name.

It added that Kim was "under detention by a relevant law enforcement body which is conducting detailed investigation into his crimes".

The confirmation of Kim's detention comes as Pyongyang issues increasingly belligerent rhetoric in a tense stand off with the administration of new US President Donald Trump. 

Kim had been teaching accounting at the Pyongyang University of Science and Technology (PUST), which said last month that the professor had been held. 

The school - founded by evangelical Christians from overseas and opened in 2010 - is known to have a number of American faculty members.

Fellow US citizen Otto Warmbier is also being held in North Korean custody.