North Korea has detained a US citizen for “hostile acts” — its second arrest in a fortnight of an American as tensions rise between Pyongyang and Washington.

Kim Hak Song was detained on Saturday, the state news agency KCNA reported. “A relevant institution is now conducting detailed investigation into his crimes,” it added.

It said Kim had worked for the Pyongyang University of Science and Technology (PUST).

The two-paragraph report gave no further details of the arrest of Kim Hak Song.

Last Wednesday the North confirmed the arrest on April 22 of Kim Sang-Duk, or Tony Kim, for trying to “overturn” the regime.

The arrest of Kim Hak Song means four US citizens are currently being held in the North.