SEOUL, South Korea–China's vice foreign minister met with North Korea's top diplomats in Pyongyang on Friday, state media said, as the nuclear-armed state has accelerated its weapons testing and threats toward Seoul in recent months.

Beijing is North Korea's biggest economic benefactor and a traditional ally, and leader Kim Jong Un has sought to shore up his country's relationship with China while intensifying his aggressive rhetoric toward the South.

The weapons tests and Kim's designation of Seoul earlier this month as the North's "principal enemy" have raised tensions in the region and led South Korean President Yoon Suk Yeol to pull closer to long-standing ally Washington.

The United States has also warned of "growing and dangerous" military ties between Pyongyang and Moscow and called on Beijing to restrain the North.

AFP photos showed China's Sun Weidong and his delegation meeting with North Korean Vice Foreign Minister Pak Myong Ho and others at the People's Palace of Culture in the capital.

Pak greeted Sun with a smile as the Chinese vice foreign minister entered a room in the venue in the North Korean capital.

While the two shook hands, photographers at the scene captured the moment, AFP videos showed.

North Korean Foreign Minister Choe Son Hui was present, the North's official Korean Central News Agency said early Saturday in a brief readout of the meeting.

The members of the Chinese delegation were seen taking notes during the meeting, AFP footage showed, as they sat across from their North Korean counterparts in a spacious room adorned with a large painting of a wooded valley, with each participant provided a water bottle and a glass.

The two sides agreed to "continue to strengthen tactical cooperation and keep pace with each other to defend the common core interests", KCNA said in its report.

- 'A new page' -

Sun's visit comes as US National Security Advisor Jake Sullivan was set to meet Chinese Foreign Minister Wang Yi in Thailand, as the two powers seek to improve relations after years of tensions.

Earlier this month, Kim said Pyongyang and Beijing had designated 2024 as the "year of DPRK-China friendship," using the acronym of the North's official name.

The two countries "will further promote exchange and visits in all fields, including politics, economy and culture" this year, and add "a new page to the history of the DPRK-China relations," Kim said in his message to Chinese President Xi Jinping, according to KCNA.

His rhetoric toward the South has been in stark contrast to the friendly relations with Beijing -- Kim has declared Seoul his country's "principal enemy", and jettisoned agencies dedicated to reunification and outreach.

He also threatened war over "even 0.001 mm" of territorial infringement.

Seoul, Tokyo and Washington have held joint military exercises against the growing North Korean threats, while Beijing last year sent senior officials to attend Pyongyang's military parades.

As permanent members of the UN Security Council, both China and Russia have been obstructing efforts led by Washington to impose stricter sanctions on North Korea in response to its increased weapons testing activities in recent months.

Kim also successfully put a spy satellite into orbit late last year, after receiving what Seoul said was Russian help, in exchange for arms transfers for Moscow's war in Ukraine.