US President Joe Biden has indicated he will not send US forces to Ukraine to counter the Russian invasion, because that could lead to a war on a global scale. He also warned that Russia will have to pay a serious and lasting price for its action.

Biden made the remarks in an interview with a social media influencer, which was released on Saturday.

About possible responses to Russia's aggression, Biden said, "You have two options. Start a third world war, go to war with Russia, physically. Or two, make sure that a country that acts so contrary to international law ends up paying a price for having done it."

He acknowledged that no sanction can be expected to have an immediate effect, but said the economic and political sanctions imposed on Russia are the broadest sanctions in history.

He pointed out that NATO is more unified than ever, and that Russian President Vladimir Putin is "producing the exact opposite effect that he intended."

Biden also said, "Russia will pay a serious price for this short term and long term, particularly long term."

Meanwhile, the UN Security Council is set to meet on Sunday to vote on a request to hold an emergency special session of the 193-member General Assembly to discuss Russia's invasion of Ukraine.

The United States is one of the nations that made the request.

The vote is procedural, and permanent council members cannot exercise their vetoes. It needs approval from at least nine council members, and is expected to pass.

Washington appears to be aiming to increase pressure on Russia by highlighting its isolation on the international stage.