President Joe Biden and Ukrainian President Volodymyr Zelenskyy are both speaking Tuesday at the United Nations General Assembly.

In his address, delivered shortly after 10 a.m., Biden made a robust case that the world must remain united in defending Ukraine against Russian aggression.

He warned that no nation can be secure if “we allow Ukraine to be carved up” as he tries to rally support for Kyiv’s effort to repel a nearly 19-month-old Russian invasion that has no end in sight.

The U.S. president called on world leaders to not let support for Ukraine diminish, arguing that Russia is counting on countries to grow tired of prolonged conflict in Kyiv which will “allow it to brutalize Ukraine without consequence.” Russia alone is standing in the way of a resolution, Biden argued, saying that Moscow’s price for peace was “Ukraine’s capitulation, Ukraine’s territory and Ukraine’s children.”

“I ask you this: If we abandon the core principles of the United States to appease an aggressor, can any member state in this body feel confident that they are protected?” Biden said in his address. “If we allow Ukraine to be carved up, is the independence of any nation secure?”

Biden’s appearance came the day after his visit to Midtown Monday night where he declared that “Broadway is back.”

The president took the stage at the Lunt-Fontanne Theater, which is currently home to the Josh Groban musical, Sweeney Todd.

This was a fundraiser hosted by some of Broadway’s biggest stars.

“I have never been more optimistic about Americas future than in the 800 years I’ve served,” Biden joked at the event.

First Avenue was closed early Tuesday morning in preparation for Biden’s motorcade, which arrived during rush hour traffic.

Though the General Assembly is a high stakes meeting, New York City commuters have not been to pleased with the gridlock.

Ukraine’s President Zelenskyy spent Monday visiting Staten Island University Hospital, where 18 Ukrainian soldiers have been treated.

At the U.N. General Assembly later in the day, he was expected to urge more support for the war effort and question why Russia is still a permanent member of the UN Security Council.

“It’s very important that all our words, all our messages will be heard by our partners. And if in the United Nations still, it’s a pity but still there is a place for Russian terrorists. It’s a question not to me. I think it’s a question to all the members of the United Nations,” Zelenskyy said.

After appearing at the United Nation, Zelenskyy is headed to Washington to lobby Congress for more funding.