North Korea announced Sunday it has detained a fourth US citizen over unspecified hostile acts against the country - the second American detention announced this week.

Kim, who manages the school's experimental farm at the college of agriculture and life sciences, was detained on route by train from Pyongyang to China's border town of Dandong, the university's co-founder Chan-Mo Park told Reuters.

Earlier this month, American colleague Kim Sang-duk, who is also known as Tony Kim, was arrested on similar charges.

North Korea has long sought direct diplomatic engagement with the United States over its nuclear weapons program and may now be arresting more USA citizens to incite the Trump administration to dispatch a high-level envoy to the country. USA tourist Otto Warmbier is serving 15 years imprisonment with hard labor over the theft of a political propaganda poster in January 2016 and Kim Dong Chul, a Korean-American businessman, is serving 10 years on espionage charges.

The U.S. policy of trying to isolate and pressure the North Korean regime could face another tough challenge as South Korea looks set to elect a new president, Moon Jae-in, who favors engagement with his northern neighbor.

The so-called track two talks would be the first since U.S. President Donald Trump took office in January and come at a time of tensions over North Korea's efforts to develop a nuclear missile that can hit the United States.

Kim Hak-song, an ethnic Korean, born in Jilin, China, and educated at a university in California, was detained Saturday on suspicion of "hostile acts" against the regime, state media reported.

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After Hennick told him such language wasn't acceptable and the man asked why not, Hennick reported the man to an usher. The man who received the ban reportedly denied using the slur.

Now, with the detention of the second Korean-American working at Pyongyang University in barely two weeks, a tearful Kim Mi-ok had a message for the North Korean government.

Former Secretary of State Condoleezza Rice on Tuesday said the Trump Administration is "doing as well as anybody could" as it grapples with the North Korean nuclear program.

The administration also claimed that the Central Intelligence Agency bribed a North Korean citizen $40,000 (£32,000) to carry out the assassination.

A North Korean flag flies on a mast at the Permanent Mission of North Korea in Geneva October 2, 2014. "He went to Pyongyang to devote himself to the development of North Korea's agricultural technology so that the North can be self-sufficient with food", David Kim explained. He was accused of stealing a propaganda poster, and North Korean officials released a video that purported to show him taking it.

North Korea does not hide its willingness to return to the negotiating table with the United States.

"He was a very diligent, hardworking man determined to help people in North Korea", he said.