President Biden warned world leaders Wednesday that a nuclear war "cannot be won and must never be fought," as he accused Russia of violating the United Nations international charter in its "brutal, needless war" against Ukraine, and stressed that the U.S. "does not seek conflict" or a "Cold War" with China.

Biden, speaking to the United Nations General Assembly in New York City on Wednesday, reflected on the past year.

"In the last year, our world has experienced great upheaval — growing crisis and food insecurity; record heat, floods, droughts, COVID-19, inflation, and a brutal, needless war — a war chosen by one man," Biden said in his first words to UNGA.

BIDEN TO ARGUE RUSSIA HAS VIOLATED UN’S ‘CORE TENETS’ AS PUTIN ESCALATES MOBILIZATION

President Biden delivers UN General Assembly speech

President Biden addresses the 77th session of the United Nations General Assembly at the U.N. headquarters in New York on Wednesday. (AP Photo/Evan Vucci)

"To be very blunt, let us speak plainly. A permanent member of the United Nations Security Council invaded its neighbor, attempted to erase a sovereign state from the map," Biden said. "Russia has shamelessly violated the core tenets of the United Nations Charter — no more important than the clear prohibition against countries taking the territory of their neighbor by force."

Biden, speaking of Vladimir Putin by name, said the Russian president has made "overt nuclear threats against Europe and a reckless disregard for the responsibilities of the nonproliferation regime." 

"Now, Russia is calling more soldiers to join the fight and the Kremlin is organizing a sham referendum to try to annex parts of Ukraine — an extremely significant violation of the U.N. charter," Biden said, urging the world to "see these outrageous acts for what they are."

TOP MILITARY BRASS IN UKRAINE'S SOUTH CALLS FOR VOLUNTEERS AS FORCES LOOK TO TAKE BACK KHERSON

"Putin claims he had to act because Russia was threatened," Biden said. "But no one threatened Russia — no one other than Russia sought conflict. In fact, we warned it was coming."

Vladimir Putin speaks at meeting in Sochi, Russia

Russian President Vladimir Putin chairs a meeting on the country's transport industry via a video link in Sochi, Russia, on May 24, 2022. (Sputnik/Mikhail Metzel/Kremlin via REUTERS)

He added: "And, with many of you, we worked to try to avert Putin’s own words, make his true purpose unmistakable just before he invaded." 

Biden said that the war has provided "horrifying evidence of Russia’s atrocities and war crimes," pointing to the discovery of mass graves in Ukraine filled with bodies "showing signs of torture."

"This war is about extinguishing Ukraine’s right to exist as a state — plain and simple — and Ukraine’s right to exist as a people," Biden said. "Whoever you are, wherever you live, whatever you believe that should not, that should make your blood run cold."

Biden touted the U.S.’ efforts to lead the way in marshaling "massive levels of security assistance and humanitarian aid and direct economic support for Ukraine," along with support from allies and partners around the world who have contributed "to help Ukraine defend itself." 

"The United States is also working closely with our allies and partners to impose costs on Russia to deter attacks against NATO territory to hold Russia accountable for the atrocities and war crimes," he said.

"If nations can pursue their own imperial ambitions without consequences, then we put at risk everything this very institution stands for," Biden stressed.

BIDEN CALLS ON UN TO EXPAND PERMANENT MEMBERS OF SECURITY COUNCIL

The president, though, said that the world has been "tested," but said "we did not hesitate."

"We chose liberty. We chose sovereignty. We chose principles, to which every party to the United Nations charter is beholding," Biden said. "We stood with Ukraine."

"Like you, the United States wants this war to end on just terms — on terms we all signed up for — that you cannot seize a nation’s territory by force," he said. "The only country standing in the way of that is Russia." 

Biden added: "Ukraine has the same rights that belong to every sovereign nation. We will stand in solidarity with Ukraine. We will stand in solidarity against Russia’s aggression. Period."

China's Xi Jinping at meeting wearing black suit

Chinese President Xi Jinping attends a commendation ceremony for role models of the Beijing Winter Olympics and Paralympics at the Great Hall of the People in Beijing on April 8, 2022. (AP Photo/Ng Han Guan)

Shifting to his world view, the president said "it is no secret that the contest between democracy and autocracy, the United States, and I as president, champion a vision for our world that’s grounded in the values of democracy."

"The United States is determined to defend and strengthen democracy at home and around the world because I believe democracy remains humanity's greatest instrument to address the challenges of our time working with the G7 and like-minded countries to prove democracies can deliver for their citizens, but also deliver for the rest of the world as well," Biden said.

President Biden stressed that the U.N. charter, "the very basis of a stable and just rule based order, is under attack by those who wish to tear it down or distorted for their own political advantage."

"And the United Nations charter was not only signed by democracies of the world, was negotiated among citizens, dozens of nations with vastly different histories and ideologies united and their commitment to work for peace," he added.

Iran Nuclear inspection Hassan Rouhani

Former Iranian President Hassan Rouhani, second right, listens to head of the Atomic Energy Organization of Iran Ali Akbar Salehi while visiting an exhibition of Iran's new nuclear achievements in Tehran, Iran, in April 2021. (Iranian Presidency Office/AP)

"I reject the use of violence and war to conquer nations or expand borders through bloodshed, to stand against global politics of fear and coercion, to defend the sovereign rights of smaller nations as equal to those of larger ones," Biden said.

As for China, President Biden said the U.S. will "conduct itself as reasonable." 

"We do not seek conflict. We do not seek a Cold War. We do not ask any nation to choose between the United States or any other partner," he said.

Biden stressed, however, that the U.S. "will be unabashed in promoting our vision of a free, open, secure and prosperous world and what we have to offer communities of nations investing to designed not to foster dependency, but to alleviate burdens and help nations become self-sufficient."

Biden went on to say that the U.S. will "lead with our diplomacy to strive for peaceful resolution of conflicts," and stressed that his administration seeks to "uphold peace and stability across the Taiwan Strait, remain committed to our One China Policy, which has helped prevent conflict for four decades." 

"We continue to oppose unilateral changes to the status quo by either side," he said.

President Biden delivers UN General Assembly speech

President Biden addresses to the 77th session of the United Nations General Assembly at U.N. headquarters in New York on Wednesday, (AP Photo/Mary Altaffer)

Meanwhile, as for nuclear proliferation, Biden said "a nuclear war cannot be won and must never be fought."

"Today, we’re seeing disturbing trends," he said, pointing to Russia’s recent nuclear threats and China conducting "an unprecedented concerning nuclear buildup without any transparency."

In a swipe at North Korea, Biden said that despite U.S. "serious" efforts and "sustained diplomacy," the DPRK "continues to blatantly violate U.N. sanctions."

Shifting to the Iran nuclear deal, Biden said that his administration "will not allow Iran to acquire a nuclear weapon."

The Biden administration has engaged in negotiations to revive the Joint Comprehensive Plan of Action (JCPOA), also known as the Iran nuclear deal. The deal contains no provisions to stop Tehran’s sponsorship of terrorism across the globe.

Former President Donald Trump’s administration withdrew from the deal in 2018.

CLICK HERE TO GET THE FOX NEWS APP

"I believe that diplomacy is the best way to achieve this outcome," Biden said. "We cannot let the world now slide backwards, not can we turn a blind eye to the erosion of human rights."

In closing, the president said that the challenges faced by world leaders are "great, but our capacity is greater. Out commitment must be greater still." 

"Let’s stand together to again declare… the nations of the world are united still, and we stand for the values of the U.N. Charter," Biden said. "And we still believe by working together we can bend the arc of history toward a freer and more just world for our children." 

He added: "Although none of us have fully achieved, we’re not passive witnesses to history. We are authors of history." 

"We can do this. We have to do this. For ourselves, and for our future, for humankind," Biden said.