Foreign ministers from the G20 group of nations gathered in Rio de Janeiro on Wednesday to discuss world tensions and ways to improve multilateral organizations in preparation for their annual leaders' summit presided by Brazil.

Brazilian President Luiz Ignacio Lula da Silva has made reform of global governance a top priority for the G20 this year, along with curbing climate change and reducing poverty.

But with continued fighting between Russia and Ukraine and the war in Gaza, diplomats are not optimistic that proposals to upgrade global governance will advance easily within the group of the world's largest economies.

U.S. Secretary of State Antony Blinken met with Lula in Brasilia on his way to the Rio meeting and expressed U.S. support for his G20 presidency agenda to combat hunger and poverty, mobilize against the climate crisis, and make global governance more effective, spokesperson Matthew Miller told reporters.

The top U.S. diplomat discussed the conflicts in Gaza with Lula, amid a diplomatic spat after the Brazilian leader likened Israel's war in Gaza to the Nazi genocide during World War Two.

Lula has criticized the United Nations for failing to resolve the conflict between Israel and the Palestinians, and his accusations last week of atrocities by Israel in Gaza triggered a diplomatic crisis with an Israeli reprimand and Brazil recalling its ambassador.