It is difficult to predict if leaders of the G20 grouping gathering for a summit in New Delhi this weekend can reach a consensus on a declaration, European Council President Charles Michel said on Friday.
Analysts say deeper and more entrenched divisions over Russia's war in Ukraine risk derailing progress on issues such as food security, debt distress and global cooperation on climate change when the world's most powerful nations meet.
"It's difficult to predict if it will be possible to have an agreement on the declaration," Michel told a press conference in the Indian capital. "We are still negotiating.
"I don't intend to say something that will make the efforts more difficult. We support the efforts made by the Indian presidency."
India, which is chairing the grouping, wants the summit's final communique to also accommodate the views of Russia and China, which have blocked Western nations' efforts to include strong condemnation of Russia's invasion of Ukraine.
Neither Russian President Vladimir Putin nor Chinese President Xi Jinping is attending the summit, with Moscow sending instead Foreign Minister Sergei Lavrov while Premier Li Qiang will represent Beijing.
Michel said the European Union wanted the G20 to focus on tackling global challenges to food and energy security, saying Russia was blocking Ukraine's exports of grain through the Black Sea, one of the key issues to feature in the weekend's talks.
"The EU will continue to strongly back Ukraine and pile pressure on Russia," he said, adding that it was crystal clear that the bloc condemned the Russian aggression.
"By deliberately attacking Ukraine's ports, the Kremlin is depriving people of food they desperately need."
Russia withdrew from the UN-brokered Black Sea grain deal in July, citing a lack of progress on its own food and fertiliser exports.
Michel did not foresee the summit solving all "major" global problems, he said, but added that the EU wanted the bloc to hasten efforts on sustainable development, climate change and poverty reduction.