WASHINGTON

The US estimates a further invasion of Ukraine could displace 5 million people, Washington’s envoy to the UN Linda Thomas-Greenfield said Wednesday.

"If Russia continues down this path, it could, according to our estimates, create a new refugee crisis, one of the largest facing the world today, with as many as 5 million more people displaced by Russia's war of choice and putting pressure on Ukraine's neighbors," Thomas-Greenfield told the UN General Assembly.

She also said that Ukraine is one of the world's largest wheat suppliers, especially for the developing world and Russia's actions could cause a spike in food prices and lead to even more desperate hunger in places like Libya, Yemen and Lebanon.

"Now it's not the time to sit on the sidelines. Now is the time to get off of the sidelines. Let us together show Russia that it is isolated and alone in its aggressive actions," she added.

Russian President Vladimir Putin on Monday announced that Moscow was recognizing Luhansk and Donetsk as "independent" states, followed quickly by sending Russian forces there to "maintain peace."

The announcements drew widespread global condemnation as violations of the UN Charter and international law, with Western countries announcing new sanctions on Russia.

In 2014, after invading Ukraine's Crimean Peninsula, Moscow began to support separatist forces in eastern Ukraine against the central government, a policy that it has maintained for the past seven years. The conflict has taken more than 13,000 lives, according to the UN.

Putin's latest moves follow Russia amassing 100,000 troops and heavy equipment in and around its neighbor, with the US and Western countries accusing it of setting the stage for an invasion.

Russia has denied it is preparing an invasion and instead claims the West has undermined its security through NATO's expansion toward its borders.