JOHANNESBURG (Kyodo) -- Foreign ministers of the Group of 20 countries met in South Africa on Thursday to discuss Russia's war in Ukraine and other global affairs, with the rare absence of the top U.S. diplomat leaving room for China and Russia to expand their outreach to developing and emerging economies.

The first day of the two-day meeting centered on global geopolitics including Ukraine, with Japanese Foreign Minister Takeshi Iwaya vowing to continue support for Kyiv while also expressing hope that ongoing diplomatic efforts to negotiate peace will help bring an end to the nearly three-year war.

The gathering in Johannesburg is taking place amid a growing rift between Washington and Kyiv as the U.S. administration of President Donald Trump negotiates with Russia to end the war without Ukraine's participation in the talks. European nations have also expressed concern about being sidelined.

U.S. Secretary of State Marco Rubio is boycotting what would have been his G20 talks debut having accused the African nation of "anti-Americanism," reflecting the Trump administration's lack of interest in multilateral frameworks.

In his opening address, South African President Cyril Ramaphosa expressed concern that conflict and war, climate change and food insecurity "threaten an already fragile global coexistence," noting "a lack of consensus among major powers, including in the G20, on how to respond to these issues of global significance."

"As the G20, it is critical that the principles of the U.N. Charter, multilateralism and international law remain at the center of all our endeavors," he said.

South Africa holds the group's rotating presidency this year, the first time for an Africa country.

During the meeting, China's top diplomat Wang Yi stressed solidarity with countries including South Africa, as Beijing has been promoting its Belt and Road global infrastructure initiative utilizing financial aid for developing economies.

He also expressed his support for the recent U.S.-Russia talks on the war in Ukraine as "efforts toward peace," adding he expects a "sustainable and lasting solution" to be found.

Wang said Beijing will play a "constructive role" in resolving the Ukraine war.

In a meeting on the sidelines of the multilateral gathering, Wang agreed with Russian Foreign Minister Sergey Lavrov to strengthen the countries' "comprehensive strategic partnership of coordination," according to China's official Xinhua News Agency.

According to the Japanese government, Iwaya told his G20 counterparts that Japan will "contribute to Ukraine's medium- to long-term recovery and reconstruction support" as part of efforts to achieve peace.

"Regarding Russia's aggression against Ukraine, various diplomatic efforts are currently ongoing to achieve peace, and we hope that these efforts will lead to an end to the prolonged combat and help achieve a breakthrough in this difficult situation," he was quoted as saying.

While expressing his serious concern about cooperation between Russia and North Korea, including the deployment of North Korean troops in support of Russia's war, Iwaya said "unilateral attempts to change the status quo by force should never be tolerated anywhere" in the world, amid China's assertiveness in the Indo-Pacific region.

He also said the G20 should play a key role "to lead the world to cooperation rather than division" and that Japan hopes to "seek common ground through dialogue and advance concrete coordination."

The G20 groups Argentina, Australia, Brazil, Britain, Canada, China, France, Germany India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, and the United States, plus the European Union and African Union.

Iwaya held a meeting with his Brazilian counterpart Mauro Vieira, agreeing to strengthen bilateral relations in the fields of trade and investment, the Japanese Foreign Ministry said.

Iwaya also pledged to work toward the success of a key U.N. climate conference that Brazil will chair in November, the ministry said.