In a meeting held in Hanoi on the second leg of Kishida's eight-day tour covering Southeast Asia and Europe, the two premiers also confirmed their commitment to closer bilateral cooperation in the security and economic fields.

"We confirmed that countries must abide by the principle of respecting the independence and the sovereignty of states," Kishida said in a joint press conference after the talks, adding, "In any region, changing the status quo by force is not permissible."

Kishida said the two sides agreed on the importance of an immediate ceasefire in Ukraine and the provision of humanitarian aid, adding that they "strongly oppose threats and uses of weapons of mass destruction and attacks on civilians."

In the run-up to Kishida's visit, the focus was on whether the two could agree to work together over Russia's aggression. Japan is stepping up sanctions on Moscow in coordination with other Group of Seven nations, but Vietnam is known for its traditional ties with Moscow since the Soviet era.

Hanoi abstained in a UN vote in March on a resolution condemning Russia's invasion of Ukraine.

Kishida said the two leaders also agreed to strongly oppose attempts to change the status quo in the South China Sea at a time when the region faces an increasingly assertive China.

Kishida has repeatedly said Russia's invasion has shaken the foundation of international order and said before heading for Indonesia on Friday that his trip, also covering Thailand, Italy and Britain, is aimed at building peace. Kishida arrived in Hanoi on Saturday.

The two last held a meeting when Chinh was invited to Japan in November after Kishida became prime minister in the previous month.