North Korea has said it will deport an American citizen it detained for illegal entrance, an apparent concession to the US that came even as it announced the test of a new “ultramodern” weapon that will be seen as a pressuring tactic by Washington.

The two announcements, which seemed aimed at both appeasing and annoying Washington, suggest Pyongyang wants to keep alive dialogue with the US even as it struggles to express its frustration at stalled nuclear diplomacy.

North Korea in the past has held arrested American citizens for an extended period before high-profile US figures travelled to Pyongyang to secure their freedom.

A photo showing North Korea’s missile launch is displayed at the Unification Observation Post in Paju
A photo showing North Korea’s missile launch is displayed at the Unification Observation Post in Paju (Ahn Young-joon/AP)

Last year, American university student Otto Warmbier died days after he was released in a coma from North Korea after 17 months in captivity.

On Friday, the Korean Central News Agency said American national Bruce Byron Lowrance was detained on October 16 for illegally entering the country from China.

It said he told investigators he was under the “manipulation” of the CIA.

A short KCNA dispatch said North Korea decided to deport him but did not say why and when.

South Korean soldiers at the border fence
South Korean soldiers at the border fence (Ahn Young-joon/AP)

The North’s decision matches its general push for engagement and diplomacy with the US this year after a string of weapons tests in 2017, and a furious US response, had some fearing war on the Korean peninsula.

In May, North Korea released three American detainees in a goodwill gesture weeks ahead of leader Kim Jong Un’s June 12 summit with President Donald Trump in Singapore.

The three Americans returned home on a flight with US secretary of state Mike Pompeo. Weeks after the summit, North Korea returned the remains of dozens of presumed US soldiers killed during the 1950-53 Korean War.

The US, South Korea and others have previously accused North Korea of using foreign detainees to win diplomatic concessions.

Some foreigners have said after their release that their declarations of guilt had been coerced while in North Korean custody. Mr Warmbier and other American detainees in the North were imprisoned over a variety of alleged crimes, including subversion, anti-state activities and spying.

The latest detained American is likely to be a man South Korea deported last year, according to South Korean police.

In November 2017, a 58-year-old man from Louisiana was caught in South Korea after spending two nights in the woods in a civilian-restricted area near the border with North Korea. The name written in his passport was Lowrance Bruce Byron, said police at Gyeonggi Bukbu Provincial Police Agency.

Before his deportation, the man told interrogators that he “knows lots of people in the Trump administration so that he wants to work as a bridge between the United States and North Korea to help improve their ties worsened by Warmbier’s death”, said one of the police officers who investigated the man.

Earlier on Friday, KCNA said Mr Kim observed the successful test of an unspecified “newly developed ultramodern tactical weapon”, although it did not describe what the weapon was.

It did not appear to be a test of a nuclear device or a long-range missile with the potential to target the US. A string of such tests last year pushed always uncomfortable ties on the peninsula to unusually high tension before the North turned to engagement and diplomacy.

Experts say the weapon test was probably an expression of anger by North Korea at US-led international sanctions and small-scale military drills between South Korea and the US.

It is the first publicly known field inspection of a weapons test by Mr Kim since he observed the testing of the Hwasong-15 intercontinental ballistic missile in November last year, according to South Korea’s Unification Ministry.