"The security of USA citizens is one of the Department's highest priorities", the statement said.
North Korea's official Korean Central News Agency said Sunday that Kim Hak Song had worked for the Pyongyang University of Science and Technology before he was held on Saturday.
Two weeks earlier, North Korea detained another US citizen, Kim Sang-dok or Tony Kim, as he waited to board a flight at Pyongyang airport.
All religion is banned in North Korea, a totalitarian state that requires all its citizens to worship the three generations of the Kim family that have run the country through a freaky personality cult since the end of World War II.
"Professor Kim was a man who would call North Korea as his own country".
North Korea has detained another American who worked at a private university in Pyongyang, taking to four the number of US citizens who are being held by Kim Jong Un's regime. "For example, North Korea freed three USA citizens during visits by former Presidents Bill Clinton and Jimmy Carter in 2009 and 2010, respectively". Park Chan-mo, the chancellor of the Pyongyang University of Science and Technology, had said last month that Kim was detained by officials as he was trying to leave the country from Pyongyang's worldwide airport.
In April, KCNA said Tony Kim - also known as Kim Sang Duk - was detained for "hostile acts" toward the North Korean regime.
- South Korean-born US citizen Kim Dong Chul was sentenced in April 2016 to 10 years in prison with hard labor after being convicted of espionage.
The arrest of two Americans in such a short time comes as Pyongyang exchanges hostile rhetoric with the United States over its banned missile and nuclear weapons programmes.
Otto Warmbier, a University of Virginia student, was sentenced to 15 years of hard labor in 2016 for removing a political sign, CNN reported. I mean, that's the primary core issue that has to be addressed by the North Koreans."That does not mean, however, that the detainees will not be part of that dialogue because I - from my experience, I would say one of the first requirements we would have is to show goodwill".
On Friday, North Korea accused American and South Korean intelligence services of plotting to assassinate Kim Jong Un with "biochemical substances", in an effort to destabilize the isolated regime.