In a break with tradition for US presidents, Joe Biden did not speak on the first day as he had traveled to Britain for the funeral of Queen Elizabeth II.
But when he took the UNGA podium on Wednesday morning, he opened with a solid blow against Moscow for invading Ukraine, threatening the use of nuclear weapons, and causing a food crisis that has hit nations in Africa and elsewhere.
Biden said Russian President Vladimir Putin's attack on Ukraine since February is "a significant violation of the U.N. Charter," noting that "a prominent member of the (UN) Security Council has invaded its neighbor."
"Russian forces have attacked Ukrainian schools, railway stations and hospitals, part of Moscow's aim of "extinguishing Ukraine's right to exist as a state," Biden said.
The U.S. president went on to say "Today, Putin has made overt nuclear threats against Europe."
Biden rebuffed statements by Putin that Russia was threatened, telling the General Assembly "No one threatened Russia. No one but Russia sought conflict."
He also called a "sham" plans for Russian-controlled parts of eastern Ukraine to have "referendums" to join Russia, exiting Kyiv.
Biden took a minute, then stated with conviction "This war is about Ukraine's right to exist as a state. That should make your blood run cold."
"Russia has shamelessly violated the core tenets of the United Nations Charter," Biden said.
Biden also used his UNGA address to call for an expanded UN Security Council including nations from continents not presently represented.
"The United States supports increasing the number of both permanent and non-permanent representatives of the council," Biden told the UN General Assembly.
"This includes permanent seats for those nations we've long supported -- permanent seats for countries in Africa, Latin America, the Caribbean. The United States is committed to this vital work," he added.
The U.S. president also announced another $2.9 billion for a fund aimed at helping to resolve global food insecurity caused in part by Russia's invasion of grain-producing Ukraine.
The White House said food supplies are being dangerously disrupted by "the compounding impacts of the pandemic, the deepening climate crisis, rising energy and fertilizer costs, and protracted conflicts -- including Russia's invasion of Ukraine."
The White House stated the turmoil has "disrupted global supply chains and dramatically increased global food prices."
This report was prepared with information from UNGA, Reuters, and Agence France-Presse