HANOI, Vietnam (AP) -- Russian President Vladimir Putin is seeking to strengthen ties with longtime partner Vietnam on a state visit Thursday that comes as Moscow faces growing international isolation because of its military actions in Ukraine.

Putin was greeted by dignitaries upon his arrival in the Southeast Asian country as soldiers in white dress uniforms stood at attention. He arrived from North Korea, where he and North Korean leader Kim Jong Un signed an agreement that pledges mutual aid in the event of war.

The strategic pact that could mark the strongest connection between Moscow and Pyongyang since the end of the Cold War comes as both face escalating standoffs with the West.

In Hanoi, the Russian leader is scheduled to meet Vietnam's most powerful politician, Communist Party General Secretary Nguyen Phu Trong, the new President To Lam and other officials. The trip has resulted in a sharp rebuke from the U.S. Embassy in the country.

Much has changed since Putin's last visit to Vietnam in 2017. Russia now faces a raft of U.S.-led sanctions for its invasion of Ukraine. In 2023, the International Criminal Court in Hague issued an arrest warrant for Putin for war crimes. The Kremlin rejected it as "null and void," stressing that Moscow doesn't recognize the court's jurisdiction.

Putin's recent visits to China and now North Korea and Vietnam are attempts to "break the international isolation," said Nguyen Khac Giang, an analyst at Singapore's ISEAS-Yusof Ishak Institute.

The U.S. and its allies have expressed growing concerns over a possible arms arrangement in which Pyongyang provides Moscow with badly needed munitions for its use in Ukraine, in exchange for economic assistance and technology transfers that could enhance the threat posed by Kim's nuclear weapons and missile program.

Both countries deny accusations of weapons transfers, which would violate multiple U.N. Security Council sanctions that Russia previously endorsed.

Meanwhile, Russia is important to Vietnam for two reasons, Giang said: It is the biggest supplier of military equipment to the Southeast Asian nation, and Russian oil exploration technologies help maintain its sovereignty claims in the contested South China Sea.

"Russia is signaling that it is not isolated in Asia despite the Ukraine war, and Vietnam is reinforcing a key traditional relationship even as it also diversifies ties with newer partners," said Prashanth Parameswaran, a fellow with the Wilson Center's Asia Program.

Hanoi and Moscow have had diplomatic relations since 1950, and this year marks 30 years of a treaty establishing "friendly relations" between Vietnam and Russia.

Evidence of this long relationship and its influence can be seen in Vietnamese cities like the capital, where the many Soviet-style apartment blocks are now dwarfed by skyscrapers and a statue of Vladimir Lenin, the founder of the Soviet Union, stands in a park where kids skateboard every evening. Many of the Communist Party's top leadership in Vietnam studied in Soviet universities, including party chief Trong.

In an article written for Nhan Dan, the official newspaper of Vietnam's Communist Party, Putin vowed to deepen the ties between Moscow and Hanoi and hailed Vietnam as a "strong supporter of a fair world order based on international law, on the principles of equality of all states and non-interference in their domestic affairs."

He also thanked "Vietnamese friends for their balanced position on the Ukrainian crisis," in the article released by the Kremlin.

Meanwhile, Vietnam's policy of "bamboo diplomacy" -- a phrase coined by Trong referring to the flexibility of bamboo plant, bending but not breaking in the shifting headwinds of global geopolitics -- is being increasingly tested.

A manufacturing powerhouse and an increasingly important player in global supply chains, Vietnam played host to both U.S. President Joe Biden and the leader of rival China, Xi Jinping, in 2023.

Vietnam has remained neutral on Russia's invasion of Ukraine. But neutrality is getting trickier, with the U.S. Embassy in Hanoi criticizing Putin's visit, saying that "no country should give Putin a platform to promote his war of aggression and otherwise allow him to normalize his atrocities." If Putin is allowed to travel freely it "could normalize Russia's blatant violations of international law," the statement said.

Vietnam needs support from the U.S. to advance its economic ambitions and diversify its defense ties, Parameswaran said. "It has to carefully calibrate what it does with Russia in an environment of rising tensions between Washington and Moscow."

Bilateral trade between Russia and Vietnam was at $3.6 billion in 2023, compared to $171 billion with China and $111 billion with America.

Since the early 2000s, Russia accounted for around 80% of Vietnam's arms imports. This has been declining over the years due to Vietnamese attempts to diversify its supplies. But to entirely wean itself off Russia will take time, said Giang.