G20 kicks off with global pact to fight hunger, poverty

Brazil's President Luiz Inacio Lula da Silva has opened the summit of the Group of 20 major economies with the launch of a global alliance to combat poverty and hunger that 81 countries have agreed to back.

As G20 leaders met at Rio de Janeiro's Modern Art Museum for two days of talks, their agenda highlighted a shifting global order as US president-elect Donald Trump returns to power.

Their discussions of trade, climate change and international security will run up against the sharp US policy changes that Trump vows upon taking office in January, from tariffs to the promise of a negotiated solution to the war in Ukraine.

In his opening remarks Lula said the devastating effects of a changing climate can be seen around the world, calling for action by leaders on hand to address global warming and poverty.

The alliance he launched, co-ordinating global efforts to eradicate hunger and poverty, is backed by the African Union and European Union, international organisations, development banks and philanthropies such as the Rockefeller Foundation and the Bill & Melinda Gates Foundation.

"Hunger and poverty are not the result of scarcity or natural phenomena ... they are the product of political decisions," said Lula, who was born in poverty and entered politics organising a metalworkers union.

Diplomats drafting a joint statement for the summit's leaders have struggled to hold together a fragile agreement on how to address the escalating Ukraine war, even a vague call for peace without criticism of any participants, sources said.

A massive Russian air strike on Ukraine on Sunday shook what little consensus they had established, with European diplomats pushing to revisit previously agreed language on global conflicts.

The United States has also lifted prior limits on Ukraine's use of US-made weapons to strike deep into Russia.

Security in Rio de Janeiro has been strengthened with troops reinforcing police for the duration of the summit.

A Brazilian army patrol came under gunfire near a Rio de Janeiro slum in the hours before the summit began, police said.

No one was injured in the incident by the hillside Cidade de Deus community 20km west of the G20 venue.

While US President Joe Biden arrives as a lame duck with just two months remaining in the White House, China's President Xi Jinping will be a central player at a G20 summit riven with geopolitical tensions amid the wars in the Gaza Strip and Ukraine.

Brazil's push for reform of global governance, including multilateral financial institutions, may also hit roadblocks with Trump, Brazilian officials said.

Biden, who visited the Amazon rainforest on his way to Rio, is set to announce a pledge to replenish the World Bank's International Development Association fund aimed at the world's poorest countries, and launch a bilateral clean energy partnership with Brazil, a senior US official told reporters.

Xi announced an initiative with Brazil, South Africa and the African Union to funnel sci-tech innovations to the Global South, Chinese state media reported on Monday.

Xi is also expected to tout China's Belt & Road initiative as it exerts its economic ascendancy.

Brazil has so far declined to join the global infrastructure initiative but hopes are high for other industrial partnerships when Xi wraps up his stay in the country with a state visit in Brasilia on Wednesday.

Trade talks around the G20 will be stoked by concerns of an escalation in the US-China trade war as Trump plans to slap tariffs on imports from China and other countries.