President Joe Biden on Monday condemned Russia's attack on Ukraine's capital.

Eight people were reportedly killed in downtown Kyiv. The U.S. accused Russia of attacking civilian targets.

"We offer our condolences to the families and loved ones of those who were senselessly killed today, as well as our best wishes for the recovery of those who were wounded," Biden said.

Ukrainian President Volodymyr Zelenskyy said he spoke with Biden on Monday. The White House had not provided a readout of the call as of early Monday afternoon.

However, Zelenskyy said, "air defense is currently the number 1 priority."

The U.S. has refused to implement a no-fly zone over Ukraine, saying it would put American troops in direct conflict with Russia.

Biden noted that the U.S. is helping Ukraine in other ways and will continue to provide support "for as long as it takes."

"Alongside our allies and partners, we will continue to impose costs on Russia for its aggression, hold Putin and Russia accountable for its atrocities and war crimes, and provide the support necessary for Ukrainian forces to defend their country and their freedom," Biden stated.

U.S. Ambassador Linda Thomas-Greenfield gave an impassioned speech in front of the U.N. General Assembly on Wednesday.

She called on Russia to stop its "unprovoked, unjustified, unconscionable war."

"We have seen videos of Russian forces moving exceptionally lethal weaponry into Ukraine, which has no place on the battlefield. That includes cluster munitions and vacuum bombs – which are banned under the Geneva Convention," she said.

Thomas-Greenfield pinned the blame directly on Russian President Vladimir Putin. She said it was his choice alone to start the war, which has led to the deaths of innocent people and a humanitarian crisis.

"It was his choice to force hundreds of thousands of people to stuff their lives into backpacks and flee the country, to send newborn babies into makeshift bomb shelters, to make children with cancer huddle in hospital basements, interrupting their treatments, essentially sentencing them to death," she said.

Thomas-Greenfield's speech came hours before the U.N. General Assembly voted to demand that Russia stop its offensive in Ukraine and withdraw all troops.

The vote Wednesday was 141 to 5, with 35 abstentions.

The countries voting with Russia included North Korea, Syria, Eritrea and Belarus.