Russia praised a G20 summit declaration that stopped short of directly criticising Moscow for the war in Ukraine and said the bloc's leaders had acted in the interest of conflict resolution as deliberations headed into a second day on Sunday.

The group adopted a consensus declaration in New Delhi on Saturday that avoided condemning Russia for the war but called on all states not to use force to grab territory. Russia says it is conducting a "special military operation" there.

"There were very difficult negotiations on the Ukraine issue; first of all, the collective position of the BRICS countries and partners worked, everything was reflected in a balanced form ...", Svetlana Lukash, the Russian G20 sherpa, or government negotiator, was quoted as saying by Russian news agency Interfax.

BRICs groups Brazil, Russia, India, China and South Africa.

In the weeks leading to the summit, G20 countries had struggled to find a consensus on the Ukraine conflict with the West demanding countries call out Moscow for its invasion of Ukraine and Russia saying it would block any resolution that did not reflect its views.

"This was one of the most difficult G20 summits in the almost twenty-year history of the forum ... it took almost 20 days to agree on the declaration before the summit and five days here on the spot," Lukash said.

"This was not only due to some disagreements on the Ukraine subject, but also due to differences in positions on all key issues, primarily the issues of climate change and the transition to low-carbon energy systems..."

A European Union official, who did not want to be identified, said on Sunday discussions on the G20 leaders' declaration went on until the last moment and the Ukraine war was the most contentious issue before a consensus was reached.

The official praised India's strong leadership, adding that Brazil and South Africa also played a crucial role in the negotiations.

U.S. President Joe Biden and British Prime Minister Rishi Sunak are among those attending the summit hosted by Prime Minister Narendra Modi, who has sought to play a pivotal role balancing the interests of the global south with those of the West.

Ukraine's foreign ministry said the Delhi declaration was "nothing to be proud of", adding that a Ukrainian presence would have given participants a better understanding of the situation.

Ukraine had asked if it could attend the summit of the world's biggest economies.

Russia's 2022 invasion of Ukraine has left tens of thousands dead, displaced millions and sown economic turmoil across the world. Moscow denies committing atrocities during the conflict.