Brad Lendon, CNN

China and Russia are both sending high level delegations to North Korea this week in a rare flurry of diplomatic activity for the secluded nation as it prepares to mark the 70th anniversary of the end of the Korean War.

North Korea sealed its borders during the coronavirus pandemic, deepening the isolation of a country that is already one of the most cut off places in the world – now its closest allies are set to visit for a moment of historic import.

Chinese Communist Party official Li Hongzhong, who is part of the party’s central policymaking committee and holds a leadership position in the top body of its rubber stamp Parliament, will lead a delegation to Pyongyang this week, according to a statement from Hu Zhaoming, spokesperson of the International Liaison Department of the Central Committee.

The visit is believed to be the highest-level delegation from China since the coronavirus pandemic.

Li will attend ceremonies marking the 70th anniversary of the armistice agreement that ended the Korean War and his visit comes after an invitation from North Korea, the statement said.

“The visit will be significant for what it says about Beijing’s support of North Korea as well as Pyongyang’s willingness to relax pandemic-era border restrictions,” said Leif-Eric Easley, professor of international studies at Ewha Womans University in Seoul.

A Russian delegation led by Defense Minister Sergei Shoigu will also visit North Korea from July 25-27 for the 70th anniversary, the Russian Defense Ministry said.

“This visit will help strengthen Russian-North Korean military ties and will be an important stage in the development of cooperation between the two countries,” the Defense Ministry said.

North Korean state newspaper KCNA also reported the upcoming “celebratory visit” for the anniversary on July 27, which North Korea calls “Victory Day.”

Both Russia and China are Pyongyang’s longtime allies.

In the fall of 1950, China sent a quarter million troops into the Korean Peninsula, supporting its North Korean ally and pushing back the combined forces of South Korea, the United States and other countries under the United Nations Command.

More than 180,000 Chinese troops died in the Korean War, or what Beijing calls the War to Resist US Aggression and Aid Korea.

The Soviet Union also supported North Korea during the war and over the decades Moscow has been a staunch ally for North Korea, especially as the two share a joint animosity towards the West.

But Easley noted that South Korea is garnering a much larger show of international support for its armistice anniversary commemorations, with representatives from 22 countries expected to attend.

US nuclear powered attack submarine Annapolis has made a port call at Jeju Naval base on July 24, 2023, according to South Korean Navyís spokesperson Jang Do-young.South Korean Defence Ministry

New missile tests, sub visit

The Chinese visit, and the ceremonies marking the 70th anniversary of the 1953 armistice that ended fighting on the Korean Peninsula, comes amid simmering tensions between North Korea and South Korea and its US ally.

Pyongyang has frequently tested missiles banned under United Nations Security Council resolutions, and on several occasions the US and South Korea have deployed military assets like nuclear-capable submarines and bombers.

North Korea continued its torrid pace of missile testing late Monday, when it fired two short-range ballistic missiles (SRBMs) from the Pyongyang area into the waters off the east coast of the peninsula, according to South Korea’s Joint Chiefs of Staff (JCS).

The missiles were launched around 11:55 p.m. local time, flying for about five minutes or 400 kilometers (248 miles) before falling into the water, according to the JCS.

The US Navy attack submarine USS Annapolis makes a port call at Jeju, South Korea, Naval Base on July 24, 2023.South Korean Defence Ministry

Earlier Monday, US Navy attack submarine USS Annapolis made a port call at Jeju Naval Base on the island off South Korea’s southern coast, according to South Korean Navy spokesperson Jang Do-young.

The sub was stopping at the island to replenish military supplies while on an operations mission, Jang said.

The Annapolis’ visit follows the much more provocative arrival of nuclear-capable ballistic missile submarine USS Kentucky at the southern South Korean port of Busan last week.

North Korea said the visit of the “boomer,” an Ohio-class ballistic missile submarine which can carry up to 20 missiles and 80 nuclear warheads, to Busan crossed a “red line” and said such provocations could produce a drastic response by Pyongyang.

“I remind the US military of the fact that the ever-increasing visibility of the deployment of the strategic nuclear submarine and other strategic assets may fall under the conditions of the use of nuclear weapons specified in the DPRK law on the nuclear force policy,” a statement from North Korean Defense Minister Kang Sun Nam posted by state media said.

North Korea silent on US soldier

Relations have been further complicated by the decision of a US soldier to cross the border between North and South Korea last week in the demilitarized zone separating the two nations.

Pvt Travis King, who was facing disciplinary action and was meant to go back to the US the day before he bolted, is believed to be the first US soldier to cross into North Korea since 1982.

On Monday, the deputy commander of the United Nations Command (UNC), Gen. Andrew Harrison, said a “conversation has commenced” with North Korea over King.

Two US officials told CNN that North Korea had acknowledged receiving contact from the UNC, a multinational military force that includes the United States which fought on the side of South Korea during the 1950-53 Korean War.

But Pyongyang does not seem to be responding to Washington directly.

The US State Department has not received a response to its messages on King, State Department spokesperson Matt Miller said on Monday. He also said it was his understanding that the US military had not received a response.

On the UNC side, Miller said it was his understanding “that there have been no new communications since last week, communications that happened in the early days,” but that the North Korean government had acknowledged receipt of the message.

“I’m not aware of any new communications, other than those that happened in the very early hours, early days after he went across the border,” Miller said at a State Department briefing Monday.

King has not been publicly seen or heard from since he crossed into North Korea last Tuesday, and North Korea has also not said anything about the status or condition of the missing soldier.

His reasons for crossing the border into one of the world’s most authoritarian places – and a country which the US does not have diplomatic relations with – have so far remained a mystery.

Easley, the Ewha Womans University professor, said any quick response from Pyongyang on the status of King was unlikely, especially in light of the armistice commemorations.

“North Korea is unlikely to engage on Travis King’s case until his interrogation and quarantine are complete, and after the Kim regime celebrates its so-called Victory Day,” Easley said.