US President Joe Biden has said only India among the Quad group of countries was "somewhat shaky" in acting against Russia over its invasion of Ukraine, as India tries to balance its ties with Russia and the West.

While the other Quad countries - the United States, Japan and Australia - have sanctioned Russian entities or people, India has not imposed sanction or even condemned Russia, its biggest supplier of military hardware. "In response to his aggression, we have presented a united front throughout the NATO and in the Pacific," Biden told a business forum on Monday, referring to Russian President Vladimir Putin.

"The Quad - with the possible exception of India being somewhat shaky on some of these - but Japan has been extremely strong, so is Australia in terms of dealing with Putin's aggression." Putin says Russia is carrying out "a special military operation" to stop the Ukrainian government from committing "genocide" - an accusation the West calls a baseless fabrication.

After a virtual summit between Australian Prime Minister Scott Morrison and his Indian counterpart, Narendra Modi, on Monday, India's foreign ministry said Australia understood India's position on Ukraine, which "reflected our own situation, our own considerations".

India has urged an end to the violence in Ukraine but has abstained from voting against its old Cold War ally Russia. Even though India has grown close to the United States in recent years, it still depends on Russia for a continuous supply of arms and ammunition amid a Himalayan border standoff with China and perennial tension with Pakistan.

India is also considering buying more Russian oil at a discount, with two Indian state companies recently ordering 5 million barrels. Indian analysts and government officials point out that European countries are buying gas from Russia.