The United States accused Moscow of committing a war crime on Wednesday by forcibly deporting Ukrainians to Russia and said it has information that Russian officials are overseeing so-called filtration operations.

"These operations aim to identify individuals Russia deems insufficiently compliant or compatible to its control," U.S. Ambassador to the United Nations, Linda Thomas-Greenfield, told the U.N. Security Council.

She said estimates from a variety of sources, including Moscow, indicate that authorities have "interrogated, detained, and forcibly deported" between 900,000 and 1.6 million Ukrainians to Russia following the Russian invasion in late February.

In July alone Washington had information that more than 1,800 children were transferred from Russia-controlled areas of Ukraine to Russia, Thomas-Greenfield said.

"The forcible transfer or deportation of protected persons from occupied territory to the territory of the occupier ... constitutes a war crime," she said. "So why are they doing this? ... to prepare for an attempted annexation."

Russia's U.N. Ambassador Vassily Nebenzia described the council meeting as a waste of time and "a new milestone in the disinformation campaign unleashed by Ukraine and its Western backers."

He said Ukrainians who travel to Russia "go through a registration rather than filtration procedure."

Nebenzia requested that the council meet again on Thursday to discuss "real threats to international peace and security caused by the supplies by foreign states of arms and military goods to Ukraine."

While Ukraine says the invasion is an imperial-style war to take over a pro-Western neighbor, Russian President Vladimir Putin has said he wants to ensure Russian security and protect Russian speakers, particularly in eastern Ukraine, where most of the fighting has taken place.

U.N., RED CROSS ACCESS

U.N. political affairs chief Rosemary DiCarlo said the accusations of deportations and filtration were "extremely disturbing" and such reports must be investigated with the cooperation of the competent authorities.

She also appealed for unimpeded access for U.N. and Red Cross officials to all people detained during the Ukraine war, adding that this "includes access to places of internment of Ukrainian prisoners of war and civilian detainees" in Russia.

Britain is concerned that "Russia may in fact be using forced deportations and displacement in an attempt, forcibly, to change the demographic makeup of parts of Ukraine," Britain's U.N. Ambassador Barbara Woodward told the council.

Senior U.N. human rights official Ilze Brands Kehris said the United Nations had "verified that Russian armed forces and affiliated armed groups subject civilians to so-called 'filtration'."

She also said that U.N. human rights officials had "documented that men and women perceived as having ties with Ukrainian armed forces or state institutions, or as having pro-Ukrainian or anti-Russian views, were subjected to arbitrary detention, torture, ill-treatment and enforced disappearance."