One more US citizen detained in DPRK

North Korea said on Sunday it has detained another U.S. citizen on suspicion of "hostile acts" against the state, which would make him the fourth American to be held by the isolated country amid heightened diplomatic tensions with Washington.

Kim Hak Song, who worked for the Pyongyang University of Science and Technology, was detained on Saturday, the North's KCNA news agency said.

"A relevant institution of the DPRK detained American citizen Kim Hak Song on May 6 under a law of the DPRK on suspension of his hostile acts against it," KCNA said.

 A third U.S. citizen, Kim Sang Dok, who was associated with the same school, was detained in late April for hostile acts, according to the North's official media.

The U.S. State Department said it is aware of the latest reported detention.

"The security of U.S. citizens is one of the department's highest priorities. When a U.S. citizen is reported to be detained in North Korea, we work with the Swedish embassy in Pyongyang," a State Department official said in an emailed statement, declining to provide further details for privacy reasons.

The reported detention comes as tensions on the Korean peninsula run high, driven by harsh rhetoric from Pyongyang and Washington over the North's pursuit of nuclear weapons in response to what it says is a threat of U.S.-instigated war.

The Pyongyang University of Science and Technology (PUST) was founded by evangelical Christians and opened in 2010. Its students are generally children of the country's elite.