President Xi Jinping urged G20 leaders on Monday to support efforts to de-escalate the war in Ukraine and reach a "political solution," state media reported.

"The G20 should support the United Nations and its Security Council in playing a greater role, and support all efforts conducive to the peaceful settlement of crises," Xi said, according to broadcaster CCTV.

He called for leaders to avoid "spillovers" from battlefields and escalation of fighting, and to help "cool the Ukraine crisis and seek a political solution."

The president's remarks at the G20 summit in Brazil come shortly after Ukraine reportedly received a US green light to launch long-range missiles provided by Washington against targets inside Russia.

In response, Russia's Foreign Ministry said any use of these missiles by Ukraine to attack Russian territory would mark a radical escalation of the conflict, fundamentally alter the nature of the war and trigger "an adequate and tangible" response from Russia.

In his speech, Xi also called for efforts to shore up multilateral trade systems and warned against politicising economic issues.

He called for more international governance and cooperation on AI, saying this should not become "a game of rich countries and the wealthy."

Earlier in the day, the president touted China's support for the developing world and pledged more aid initiatives, including proposing an initiative with three other G20 members to help the Global South gain better access to scientific and technological innovations.

At a session on the reform of global governance institutions, Xi warned against protectionism in the name of green and low-carbon development, referring to tariffs on Chinese products like electric vehicles and biodiesel imposed by G20 members.

"We need to improve global trade governance and build a world economy characterised by openness," Xi was quoted as saying by Xinhua. (Agencies)