By Staff, Agencies The United States has expelled 12 Russian diplomats at the United Nations over accusations of "espionage activities" amid escalating tensions with Moscow following Russia’s military operation in NATO-backed Ukraine. The US mission to the United Nations labeled the Russian diplomats as "intelligence operatives" who had been engaging in “espionage activities” harmful to US national security.

"The United States has informed the Russian Permanent Mission to the United Nations that we are beginning the process of expelling 12 intelligence operatives from the Russian Mission who have abused their privileges of residency in the United States by engaging in espionage activities that are adverse to our national security," Olivia Dalton, a spokeswoman for the US mission, said in a statement.

Dalton said the decision was taken in full accordance with the UN headquarters agreement.

Russian ambassador to the UN, Vassily Nebenzia, who was informed of the expulsion through a phone call he had received while participating in a press conference at UN headquarters in New York, said the diplomats were instructed to leave the US by March 7.

Accusing the US of taking "hostile" action against Russia, Nebenzia said, “This is sad news and again another demonstration of gross disrespect to the host country agreement." The US, along with European allies, have imposed sweeping sanctions against Russian banks and a several officials in response to the country’s military campaign in Ukraine.

The administration of US President Joe Biden on Friday sanctioned Russian President Vladimir Putin and Foreign Minister Sergei Lavrov directly.

On Saturday the US and European partners agreed to cut certain Russian banks from SWIFT, the high-security network that connects financial institutions around the world.

The White House said Biden discussed with world leaders during a conference call on Monday efforts to further impose "severe costs and consequences" on Russia over its military actions in Ukraine.

In a televised address on Thursday, Putin announced a “special military operation” aimed at “demilitarization” of the Donetsk and Lugansk Republics in eastern Ukraine.

A US private company said satellite images taken showed a Russian military convoy north of the Ukrainian capital of Kiev that stretched for about 64 kilometers, substantially longer than the 27 km reported earlier in the day.

Maxar Technologies also said additional ground forces deployments and ground attack helicopter units were seen in southern Belarus, less than 32 km north of the Ukraine border.

Ukrainian President Volodymyr Zelensky said it was time for the West to consider imposing a no-fly zone for Russian missiles, planes and helicopters in response to Russian shelling of the Ukrainian city of Kharkov.

The United States has ruled out sending troops to fight Russia and officials have voiced concern about further escalating tensions between the world's two biggest nuclear powers.

"A no-fly zone would require implementation," White House Press Secretary Jen Psaki told reporters.

Such a move would require "deploying US military to enforce, which would be...

potentially a direct conflict, and potentially a war with Russia, which is something we are not planning to be a part of." Zelensky said Russia had over the past five days launched 56 rocket strikes and fired 113 cruise missiles at the city.

The Ukrainian leader accused Russia of committing war crimes and said it should be brought before an international tribunal.

He said Russia continued to bombard Ukrainian cities during the first round of talks with Ukrainian officials in Belarus on Monday.

"Today, at the initiative of the Russian side, the first round of talks between Ukraine and Russia took place.

These talks took place while our territory, our cities were being bombed and shelled,” he said.

“Don't waste time.

We do not accept such tactics.

Fair negotiations can be when one side does not hit the other side with rocket artillery at the moment of negotiations." Ukrainian officials said Russian attacks in Kharkov, a city of 1.4 million people, had killed civilians, including children