Kim Dong-chul, who was born in South Korea, was arrested in October 2015 after being accused of spying.
In March, the 62-year-old had made an apparent confession in Pyongyang in front of reporters, saying he was paid by South Korean intelligence officers.
The US has previously accused North Korea of using its citizens as pawns in a diplomatic game. The North Korean government denies the accusations.
Last month, US student Otto Frederick Warmbier was jailed for 15 years for stealing a propaganda sign and “crimes against the state”.
North Korea has previously said Kim Dong-chul had a USB stick containing military and nuclear secrets on him when he was arrested in the special economic zone of Rason.
Kim Dong-chul, who used to live in Virginia, had said he was introduced to South Korean spies by US intelligence officers.
Forced public confessions by foreign prisoners are common in North Korea.
Kim Dong-chul’s imprisonment comes amid a period of high tensions. North Korea has recently conducted a series of missile tests following its fourth nuclear test in January, both of which break UN sanctions.
Pyongyang attempted to launch two mid-range ballistic missiles on April 28 which crashed shortly after their launches, prompting an emergency meeting of the UN Security Council.
It is believed North Korea will attempt a fifth nuclear test soon.
The recent burst in activity is thought to be a ramp-up to a rare party congress due to be held on May 6, where leader Kim Jong-un is expected to consolidate power.
The US House Ethics Committee has voted to release its report on former Republican Representative…
ABC News has agreed to pay $15 million to President-elect Donald Trump to settle a…
South Korea’s parliament has voted to impeach President Yoon Suk Yeol over his failed attempt…
Israeli war planes have carried out more than 100 air strikes in Syria on December…
President-elect Donald Trump has threatened to impose 100% tariffs on the BRICS countries if they…
Syrian troops have withdrawn from the city of Aleppo following an offensive by rebels opposed…