US President Joe Biden met with his G7 counterparts and Ukrainian President Volodymyr Zelenskiy on Sunday to discuss Russia's war in Ukraine and new measures to punish Moscow.

Biden, who has lauded unity among the Group of Seven large economies in standing up to Russian President Vladimir Putin, was scheduled to meet by video conference with his fellow leaders at 11:00am ET from his home in Delaware, where he is spending the weekend. A White House official said the meeting was underway.

The White House said the leaders would discuss adding to the sanctions that Western countries have imposed on Russia since its February 24 invasion.

"They will discuss the latest developments in Russia's war against Ukraine; the global impact of Putin's war; showing support for Ukraine and Ukraine's future; and demonstrating continued G7 unity in our collective response, including building on our unprecedented sanctions to impose severe costs for Putin's war," the White House said in a statement.

The meeting comes ahead of Russia's Victory Day celebrations on Monday. Putin calls the invasion a "special military operation" to disarm Ukraine and rid it of anti-Russian nationalism fomented by the West. Ukraine and its allies say Russia launched an unprovoked war.

The United States and Europe have imposed crushing sanctions on Russia since its invasion, targeting banks, businesses and individuals in an attempt to squeeze the Russian economy and limit resources being used to advance the war.