North Korean leader Kim Jong Un returned home Saturday after an unannounced visit to the Chinese border city of Dandong, where he attended a ceremony honoring Chinese soldiers killed in the Korean War and visited an automobile factory, according to Chinese state media.

The purpose of the daylong trip remained unclear, with neither Pyongyang nor Beijing announcing the visit in advance. There was no official confirmation that Kim met Chinese President Xi Jinping or Premier Li Qiang.

China’s Xinhua News Agency reported that Wang Huning, the country’s top political adviser, accompanied Kim during his visit and saw him off at the border bridge as he departed. Wang Yi, China’s top diplomat, also participated in the events.

South Korean lawmaker Youn Kun-young said he had received a briefing on Friday indicating that Kim was likely to visit China. Citing information he had received, Youn said Kim was understood to have met Li on Saturday, although Chinese state media did not confirm such a meeting.

Youn said the visit could send a "positive signal” about the possibility of a summit between Kim and U.S. President Donald Trump.

Speculation has grown that the two leaders could meet on the sidelines of the Asia-Pacific Economic Cooperation summit scheduled for November in Shenzhen, China. Such a meeting could revive diplomatic efforts over North Korea’s nuclear program, although no summit has been confirmed.

China remains North Korea’s largest trading partner and a crucial source of economic, political and diplomatic support for the isolated country, which faces extensive international sanctions over its nuclear weapons program.

Xinhua quoted Wang as saying Kim’s visit was important for consolidating public goodwill toward the longstanding friendship between the two countries, strengthening political trust and expanding cooperation.

Wang also called for closer exchanges between their populations, deeper economic cooperation and stronger strategic coordination to protect their respective sovereignty, security and development interests. He conveyed Xi’s greetings and best wishes to Kim.

The trip coincided with the anniversary of China’s entry into the Korean War, when Chinese forces fought alongside North Korea against South Korea and U.S.-led United Nations forces between 1950 and 1953. The conflict ended with an armistice in 1953, leaving the two Koreas technically at war because no peace treaty was signed.

New bridge signals closer economic ties

Kim is believed to have entered China across the New Yalu River Bridge, a four-lane crossing spanning about 3 kilometers (1.9 miles) between Dandong and the North Korean city of Sinuiju.

Although construction was completed in 2014, the bridge remained unused for years because North Korea had not completed the necessary connecting roads and customs facilities. Its opening in mid-October marked a new step in efforts to strengthen economic links between the neighboring countries.

The opening came just over a month after North Korea and Russia inaugurated their first road bridge, underscoring Pyongyang’s efforts to deepen infrastructure and economic cooperation with its key partners.

Analysts said Kim’s visit could have been intended to push Beijing to accelerate economic commitments made during Xi’s state visit to North Korea in June.

"He may also have sought Beijing’s active support and cooperation ahead of a possible summit with Trump in Shenzhen,” Yang Moo-jin, former president of South Korea’s University of North Korean Studies, told Agence France-Presse.

Xi’s June visit to Pyongyang followed back-to-back meetings in Beijing with Trump and Russian President Vladimir Putin, highlighting China’s diplomatic engagement with leaders whose governments have increasingly aligned with North Korea.

The official statements issued after Xi’s meeting with Kim did not mention denuclearization, an omission that analysts interpreted as a possible indication that Beijing was placing less emphasis on the long-standing demand for North Korea to abandon its nuclear arsenal.

Military tensions persist with South Korea

Kim’s visit to China came as tensions remained high on the Korean Peninsula, where diplomatic efforts to improve relations have made little progress.

Hours before South Korean media first reported the trip, North Korean state media said Kim had called on his military to train to become the strongest in the world.

Addressing a major military meeting in Pyongyang, Kim urged the armed forces to pursue what he described as a "Korean-style military revolution,” reinforcing his government’s emphasis on military readiness.

His remarks came after South Korea’s military proposed talks with North Korea to clarify the countries’ shared border following an explosion in the heavily fortified Demilitarized Zone.

Seoul blamed the blast, which injured South Korean soldiers, on North Korean landmines. Pyongyang has strongly rejected the accusation.

South Korea proposed military talks Friday, but North Korea had not responded to the offer. Pyongyang has also rejected Seoul’s demand for an apology over the incident, further straining relations between the two sides.

The latest tensions complicate efforts by South Korean President Lee Jae Myung to reopen dialogue with the North. Lee has repeatedly offered talks without preconditions as part of a broader effort to ease hostilities.

Nuclear program remains a diplomatic obstacle

North Korea’s nuclear arsenal remains a central obstacle to any broader diplomatic settlement involving Pyongyang, Seoul, Washington and Beijing.

Despite years of United Nations sanctions, North Korea has formally established its status as a nuclear-armed state and repeatedly declared that its nuclear weapons program is permanent and irreversible.

In September, Lee suggested that Washington consider seeking a freeze on North Korea’s nuclear program rather than insisting on its immediate elimination, potentially offering sanctions relief in return.

Supporters of such an approach see it as a possible starting point for limiting North Korea’s nuclear capabilities and reducing the risk of conflict. Critics, however, warn that it could amount to tacitly accepting Pyongyang as a nuclear power while allowing it to secure economic concessions without surrendering its weapons.

Analysts say China’s recent diplomatic posture has also raised questions about whether Beijing is moving toward a similar position.

The absence of any reference to denuclearization in the official accounts of Xi’s June visit to Pyongyang reinforced those concerns, although neither government has formally abandoned its stated position on the issue.

Kim’s latest trip to China therefore comes at a sensitive moment, as North Korea seeks to strengthen ties with Beijing, tensions with Seoul remain unresolved and speculation continues over a possible meeting with Trump.