United States President Donald Trump on Thursday hinted at the possibility of the release of three American hostages, who were detained in North Korea.


In a midnight tweet, President Trump wrote, "As everybody is aware, the past Administration has long been asking for three hostages to be released from a North Korean Labor camp, but to no avail. Stay tuned!"


The tweet comes after a report emerged that North Korea relocated three American detainees from a labour camp to a hotel on the outskirts of Pyongyang, ahead of a planned summit between President Trump and North Korean supreme leader Kim Jong-un, according to a South Korean activist, who was quoted by Yonhap News Agency as saying.


The three American citizens are -- Kim Hak-song, Tony Kim and Kim Dong-chul. They were accused of espionage or doing "hostile acts" against North Korea.


On a related note, Otto Warmbier, an American college student, who was arrested in North Korea last year for allegedly removing a political propaganda poster from a Pyongyang hotel, died after he was transferred to the US in a deep coma. Washington D.C. accused Pyongyang of Warmbier's "bad" condition, while the latter outwardly rejected it.