North Korea appears to be building new ballistic missiles despite recent warming ties with the Trump administration and pledges to denuclearise, reports say.

Unnamed US officials told the Washington Post that spy satellites had spotted continuing activity at a site that has produced ballistic missiles. 

Donald Trump met North Korea's Kim Jong-un in Singapore in June.

After the first meeting between sitting leaders from the two countries, the two men pledged to work towards denuclearisation. Trump later said North Korea was "no longer a nuclear threat".

But Trump was criticised at home for making concessions without securing any firm commitment from Kim to end the nuclear and missile programmes.

These are not the first reports that North Korea may be continuing its weapons programme, casting doubt on the real impact of the summit in Singapore.

On Monday, the Washington Post newspaper quoted officials as saying North Korea appeared to be building one or two new liquid-fuelled intercontinental ballistic missiles (ICBMs) at the Sanumdong facility near the capital, Pyongyang.

The factory is known to have produced the Hwasong-15, the first North Korean ICBM capable of reaching the US.

A North Korean expert from MIIS, Melissa Hanham, told the BBC that the facility had "regular traffic in and out of the building", adding that this "traffic pattern" on the site stayed "about the same through the Panmunjom and Singapore meetings".

This indicated that there had not been a complete stop in activity during the summit talks.

She also noted that large "brightly coloured containers" also showed up in satellite imagery, saying that "containers similar to these have appeared during previous ICBM inspections by Kim."

Hanham added that while that experts at MIIS could not "find a way to confirm the [intelligence] leak", the information has matched evidence from satellite imagery.

BDST: 2000 HRS, JULY 31, 2018
AP