Comments come after exchange of letters between US President and Kim Jong Un raised hopes talks could be revived.

The US intelligence community does not believe North Korean leader Kim Jong Un is ready to denuclearise, US Defense Intelligence Agency Director Lieutenant General Robert Ashley told Fox News in an interview on Monday.

A summit in February between Kim and President Donald Trump collapsed when the two leaders were unable to bridge differences between the demands of the United States for denuclearisation and North Korean demands for sanctions relief.

“We still continue to assess within the IC (intelligence community) that Kim Jong Un is not ready to denuclearise,” Ashley said.

Trump will visit South Korea this weekend after an exchange of letters with Kim boosted hopes for a resumption of talks aimed at ending North Korea‘s nuclear programme.

The US is demanding that North Korea abandon its nuclear weapons entirely before international sanctions are lifted. North Korea is seeking a step-by-step approach.

Trump is set to arrive in South Korea for a two-day visit on Saturday, and will meet President Moon Jae-in on Sunday, following a summit of G20 leaders in Japan, Moon’s spokeswoman, Ko Min-jung, said on Monday.

The announcement came hours after US Secretary of State Mike Pompeo said he hoped a letter Trump sent to Kim could pave the way for a revival of talks that have been stalled since February’s failed summit in Vietnam.

On Sunday, North Korea’s official Korean Central News Agency (KCNA) reported that Trump had written to Kim, who praised the letter as “excellent” and said he would “seriously contemplate the interesting content”.

The KCNA report came just two days after Kim hosted China’s President Xi Jinping, who wrapped up a highly symbolic visit to nuclear-armed North Korea on Friday.

North Korean state media said Kim and Xi discussed the political situation surrounding the Korean Peninsula and reached unspecified consensus on important issues.

Xi is expected to meet Trump during the G20 summit and analysts say the Chinese president intends to use his trip to North Korea as a way of signalling to Trump his influence with Kim.