United States Secretary of State Mike Pompeo arrived in North Korea on Friday and met officials in the capital Pyongyang, hoping to “fill in” details on how to dismantle the North’s nuclear programme, Reuters reported.

Pompeo met North Korean senior official Kim Yong Chol, who played a key role in arranging last month’s summit between US President Donald Trump and North Korean leader Kim Jong Un in Singapore. The talks lasted nearly three hours but it was uncertain if Pompeo would meet Kim Jong Un.

Pompeo said he was seeking to “fill in” some details on North Korea’s commitments towards denuclearising the Korean peninsula and maintain the momentum towards implementing the agreement from the summit, Reuters reported, quoting journalists travelling with Pompeo.

Pompeo is also expected to discuss the matter of the remains of US soldiers missing from the 1950-’53 Korean War. After the Singapore summit, Trump said Kim had agreed to send the remains back to the US.

“If they’re serious, then we can get down to the business of defining the terms of final denuclearisation,” an unidentified US intelligence official told Reuters.

Kim Jong Un had promised to work towards denuclearising the Korean peninsula during his meeting with Trump on June 12. They had also agreed to establish formal diplomatic relations.

A few weeks later, however, Trump renewed sanctions against North Korea for a year, claiming that the country still posed an “extraordinary threat”. The move came despite Trump claiming during the summit that North Korea was “already destroying a major missile site”.

A website monitoring Pyongyang released a report in late June suggesting that North Korea was continuing to carry out rapid improvements to its nuclear research facility.