US Mike Pompeo heads to Pyongang for second US-North Korean summit

US Secretary of State Mike Pompeo headed to Pyongyang Sunday for new talks with Kim Jong Un on denuclearisation and a second US-North Korean summit.

Pompeo departed from Tokyo, where he spent the first leg of a tour that will include stops in Pyongyang, South Korea and China.

"Next stop Pyongyang to meet with Chairman Kim and continue our work to fulfil the commitments made (by) POTUS and Chairman Kim," Pompeo tweeted, using an acronym to refer to US President Donald Trump.

The trip will be Pompeo's fourth to Pyongyang, as the contours of a possibly historic US-North Korea deal take shape.

On the flight to Tokyo, Pompeo said his aim was to "develop sufficient trust" between Washington and Pyongyang to inch towards peace.

"Then we are also going to set up the next summit," said Pompeo.

However, he played down expectations for a breakthrough.

"I doubt we will get it nailed but begin to develop options for both location and timing for when Chairman Kim will meet with the president again. Maybe we will get further than that," said the top US diplomat.

In June, Trump met Kim in Singapore for the first-ever summit between the countries.

No sitting US president has ever visited North Korea, which according to human rights groups remains one of the most repressive countries on Earth.

Since the Singapore summit, which yielded what critics charge was only a vague commitment by Kim towards denuclearization of the Korean peninsula, the road towards warmer ties has been bumpy.

Trump scrapped a previously planned trip by his top diplomat to Pyongyang after what he said was insufficient progress towards implementing the terms of the Singapore declaration.

But the unorthodox US president has since declared himself "in love" with Kim.

While the US has pushed to maintain pressure on the North until its "final, fully verifiable denuclearisation", analysts say Washington may consider new options as China, Russia and South Korea seek to relax sanctions.

"North Korea took some steps towards denuclearisation and the US will face criticism from the international community if it continues to demand complete denuclearisation without any lifting of sanctions," said Yang Moo-jin, a professor at the University of North Korean Studies in Seoul.

"We can't rule out the possibility that Washington... may move in the direction of partial easing of sanctions based on progress in denuclearization," he said.

Speaking alongside Japanese Prime Minister Shinzo Abe, Pompeo said the two historic allies would have a "fully coordinated, unified view of how to proceed, which will be what is needed if we are going to be successful on denuclearising North Korea." Japan, which has seen North Korean missiles fly over its territory and been threatened with annihilation, has historically taken a hard line on Pyongyang and stressed the need to maintain pressure on the regime.

More recently, however, Abe has said the only way to improve strained ties is a face-to-face meeting with former international pariah Kim.

After Pyongyang, Pompeo travels to South Korea, whose dovish president Moon Jae-in has served as a go-between for the two sides.

South Korean Foreign Minister Kang Kyung-wha has given a hint of what a grand bargain between the two countries could look like.

In an interview with the Washington Post, she said the North could agree to dismantle Yongbyon, its signature nuclear site.

In exchange, the United States would declare a formal end to the 1950-53 Korean War -- which concluded with an armistice rather than a peace treaty -- but North Korea would stop short of delivering an exhaustive list of its nuclear facilities, she said.

Pompeo, who has repeatedly declined to be drawn publicly on the shape of an eventual agreement, did not discuss the possible outlines of a deal, saying only that his "mission is to make sure that we understand what each side is truly trying to achieve".

After Seoul, Pompeo ends his trip Monday in China, North Korea's political and economic lifeline.

The Beijing stop could be tense as it comes days after Vice President Mike Pence delivered a blistering speech accusing China of military aggression, commercial theft, rising human rights violations and electoral intervention against Trump. 

(With inputs from agencies.)