But his visit comes at a key moment for China.

“China sees itself as the logical big power in the region,” said Jung Pak, a former deputy national intelligence officer at the National Intelligence Council who has led US intelligence agencies’ strategic analysis on Korean issues.

But, Pak said, Beijing sees the US’s deployment of the Terminal High Altitude Area Defence system – or THAAD – and its potential trilateral security cooperation with South Korea and Japan, as an attempt to contain China. That means it’s in the country’s interest to erode America’s position in the region.

In exchange for cooperating with the US on the long-term removal of Pyongyang’s nuclear weapons, Beijing could try to diminish the US’s military presence on the peninsula by seeking a permanent freeze on US-South Korea joint military exercises and the removal from South Korea of the US’ anti-missile defence system, analysts said.

It also could continue to question Washington’s need to keep troops stationed on the peninsula, they said.

Trump has already said he suspects that China “could be influencing” Kim’s moves in denuclearisation talks with the US. North Korea’s former nuclear negotiator, Kim Kye-gwan, said in May that the country would not be pushed by the US to “unilaterally” abandon its nuclear arsenal.

Michael Green, a former Asian affairs director at the National Security Council under President George W. Bush, said at a Brookings Institution event this week that China was trying to drive a wedge between the US and its Asian allies, particularly South Korea and Japan.

Green, now both senior vice-president for Asia and Japan Chair at the Washington-based Centre for Strategic and International Studies, told the Post that China, together with Russia, had successfully convinced Trump to suspend Washington’s joint military exercises with Seoul, although “Japan’s Prime Minister Shinzo Abe asked the [US] president not to”.

The move also was made “without any prior consultation with Japan”, which Green called “really, really bad in the context of a larger geopolitical game”.

Pak, now a senior fellow and the SK-Korea Foundation chair in Korea studies at the Brookings Institution, said Chinese officials “tend to prioritise North Korea’s security concerns [over South Korea’s], saying the US’s presence on the Korean peninsula is threatening Pyongyang”.

When the US Defence Department announced in late June the “indefinite” suspension of select military exercises on the Korean peninsula, it said the move was in support of denuclearisation negotiations with North Korea, who regarded the military exercises as a rehearsal for a pre-emptive strike against Pyongyang.

China initially proposed the so-called freeze-for-freeze approach to lower the tensions, meaning the US and South Korea would suspend military exercises in exchange for North Korea’s freeze on nuclear and missile testing.

Since his Beijing visit in November, Trump had not changed the official line of not accepting the freeze-for-freeze proposal – an agreement that he said had “consistently failed in the past”.

In a further move, China has proposed to the US a four-party peace declaration involving South Korea, North Korea, the US and China to officially end the Korean war, which ended with an armistice agreement in 1953, the Korean newspaper Hankyoreh reported last week.

But Green cautioned that a “peace declaration” would have implications for the continued need for US forces on the Korean peninsula. “President Trump is clearly pressing his generals and his admirals almost every week to answer why we have forces in South Korea and also in Japan,” Green said.

Although Trump’s security advisers have repeatedly argued against a large-scale reduction of US troops in South Korea, the president privately favours withdrawing US forces from South Korea, the Washington Post reported, citing sources who have spoken to Trump about the issue.

China would also keep up its criticism of the deployment of the THAAD system in South Korea, an issue that led to a year-long stand-off between Beijing and Seoul from 2016 to October 2017.

The system’s installation angered China, causing South Korea’s tourism, cosmetics and entertainment industries to bear the brunt of the backlash, although Beijing had never specifically linked the cooling of relations to the THAAD deployment.

Beijing worries the THAAD system’s powerful radar can penetrate Chinese territory. But Green said Beijing’s real concern was that THAAD would “electronically link South Korea into the missile defence system that includes Japan, potentially Australia, maybe even Taiwan and Nato”.

The North Atlantic Treaty Organisation, or Nato, is an intergovernmental military alliance between 29 North American and European countries, in which the US is a member.

China is trying hard to block THAAD deployment to “prevent US bilateral alliances from getting closer and together [against China] in Asia and to weaken them incrementally”, Green said.

Pompeo’s visit to North Korea – his fourth since April – comes after nearly two months after his meeting with North Korea’s leader, Kim Jong-un, in Singapore, and amid frustration over the lack of progress there.

Trump said in an interview with Reuters on Monday that he still believed North Korea had taken specific steps toward denuclearisation and that he would “most likely” meet Kim again.

After the historic summit, the US indefinitely suspended select military exercises on the peninsula to lower the tensions and support Pompeo’s diplomatic outreach to North Korea.

But North Korea has repeatedly turned down a US offer to lift some sanctions or remove Pyongyang from Washington’s list of state sponsors of terrorism if North Korea cuts its nuclear weapons stockpile by 60 to 70 per cent within six to eight months, US news website Vox reported this month.

The International Atomic Energy Agency, the United Nations nuclear watchdog agency, said on Tuesday it expressed “grave concern” that North Korea was continuing to develop its nuclear weapons programme.

In announcing his visit to North Korea, Pompeo named Biegun as the new special envoy for North Korea policy, saying: “Steve will direct the US policy towards North Korea and lead our efforts to achieve President Trump’s goal of the final, fully verified denuclearisation of North Korea, as agreed to by chairman Kim Jong-un.”

Biegun, Ford’s vice-president of international governmental affairs, was a White House staffer and aide to national security adviser Condoleezza Rice during President George W. Bush’s administration. He also was an adviser to former Senate Majority Leader Bill Frist.