Washington(CNN) Russia is intentionally targeting Ukrainian civilians in its attack on the country, the US President alleged Wednesday, adding to mounting Western warnings of Moscow's brutality as the human toll of the seven-day war creeps higher.
Despite the accusation, President Joe Biden stopped short of formally saying Moscow is committing war crimes, though his envoy to the United Nations accused Russia of preparing to use banned weapons, including "cluster munitions and vacuum bombs," in Ukraine. And she issued a stark warning to invading Russian soldiers.
"Your leaders are lying to you. Do not commit war crimes," US Ambassador to the UN Linda Thomas-Greenfield said during remarks to an emergency session of the General Assembly.
"Do everything you can to put down your weapons and leave Ukraine," she implored.
Her warnings reflected the growing fear among Western officials that Russian President Vladimir Putin could be employing brutal new tactics in his war after failing to advance as quickly as expected during the invasion's earliest days.
Russia's bombing of civilian targets has intensified in the past days, sending death counts higher and leading to new fears for the capital Kyiv.
Ukraine's State Emergency Service said Wednesday more than 2,000 Ukrainian civilians have so far been killed amid Russia's ongoing invasion, though United Nations estimates have put that number much lower. The agency said some transport infrastructures, houses, hospitals and kindergartens have been "destroyed" by Russian forces over the last seven days.
Biden said it was evident civilians were being targeted by Russia.
"It's clear they are," he said, echoing an accusation made earlier by British Prime Minister Boris Johnson that Putin's forces are dropping munitions on innocent people.
Unlike Johnson, however, Biden stopped short of labeling Russia's actions a war crime.
"We are following it very closely," Biden said. "It's too early to say that."
Inside the General Assembly hall at the United Nations, Thomas-Greenfield warned Russia is "preparing to increase the brutality of its campaign," citing videos showing Russian forces moving "exceptionally lethal weaponry into Ukraine."
Her references to cluster munitions and vacuum bombs are the first US acknowledgment of those weapons being moved into the country. country. They are banned under the Geneva Convention for their destructive capacity.
A Russian thermobaric multiple rockets launcher was spotted by a CNN team south of Belgorod, Russia, near the Ukrainian border early Saturday afternoon.
These types of weapons do not use conventional ammunition. Instead, they are filled with high-temperature, high-pressure explosive. They are sometimes called "vacuum bombs" because they suck in the oxygen from the surrounding air to generate a powerful explosion and a large pressure wave that can have enormous destructive effects.
Biden was speaking a day after delivering a harsh condemnation of Putin during his annual State of the Union address. He generated bipartisan applause for his denunciation of the Russian invasion and the united response from the West in imposing punishing economic sanctions.
On Wednesday, Biden reiterated that sanctioning Russian oil exports remained a possibility, though officials have cautioned they will work to minimize the impact of such a move on US and global oil prices.
"Nothing is off the table," Biden said when specifically pressed on banning Russian oil exports.
White House press secretary Jen Psaki told CNN earlier the administration would strongly weigh the possibility of significant disruption to US and global oil markets when making a decision.
Ukrainian President Volodomyr Zelensky, who has remained in the capital Kyiv as it comes under fire, has called on the US and other Western nations to step up their sanctions packages. He has also asked for the US and other nations to enforce a no-fly zone over Ukraine, a prospect that's been rejected by the US.
Operating from a bunker, Zelensky has repeatedly said he plans to remain in the country, even as he describes himself as Russia's top target during the invasion. The US has said previously it is providing a broad range of support for Zelensky, though hasn't detailed what measures it's taking to protect him.
Biden said Wednesday it is up to Zelensky whether he wants to remain in his country as it comes under siege by Russia.
"I think it's his judgment to make and we're doing everything we can to help him," Biden said.
CNN has reported previously that the US has discussed contingency plans with Zelensky about leaving Ukraine or relocating to Lviv. Zelensky has stated repeatedly he wants to stay in the capital.
Biden and Zelensky spoke for 30 minutes on Tuesday.