The United States and other rich democracies on Sunday will bring to a close a Group of Seven gathering that has focused on undermining Russia and managing China with a show of force behind Ukrainian President Volodymyr Zelenskiy.

Zelensky will receive a hero's welcome during the closing day of the G7 summit hosted in Hiroshima, Japan, where leaders debated how to respond to a conflict that many expect only to escalate after nearly 15 months of fighting.

Western countries used the event to announce new sanctions against Moscow and vowed to pump even more weapons, military assistance and cash into the fight.

But they planned to aim the most rhetorical fire at China, Russia's most powerful ally in Asia, implicitly warning Chinese President Xi Jinping that any efforts to bully them or change the status quo in self-ruled Taiwan or the disputed South China Sea would be met with the same resolve as Russia's attempt to re-draw Ukraine's borders.

"A growing China that plays by international rules would be of global interest," the leaders said in a communique that included some of their toughest language ever as a group regarding Beijing.