The world is in perhaps greater peril than at any time since the end of the Cold War.

A beleaguered and cornered Vladimir Putin, Russian leader, is escalating his rhetoric and threatening nuclear war – the world’s literal worst-case scenario.

Putin announced Wednesday that the Russian offensive in Ukraine would be kicking it up a notch, calling up an additional 300,000 reservists to the cause. This move stops short of a complete draft but is a “partial mobilization” that will bolster the Russian army’s flagging human resources.

In the same speech, the Russian president blasted the Western world for sending aid to Ukraine and reminding the world that they are a nuclear-capable country. Putin warned, “To those who allow themselves such statements about Russia, I want to remind you that our country also has various means of destruction, and some components are more modern than those of the NATO countries.”

Putin declared that any further military bolstering of Ukraine, which Russia is expected to soon declare belongs to them now officially, would be met with any means necessary; “If the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people. This is not a bluff.”

President Joe Biden spoke before the UN Wednesday to rally allies and calm the world.

White House security advisor Jake Sullivan said ahead of Biden’s address, “He will speak to everyone around the world, those that have joined our broad-based coalition to support Ukraine and those who so far have stood on the sidelines, that now is a moment to stand behind the foundational principles of the charter.”

When Biden took the stage, he blasted Putin’s choice to launch a war against Ukraine, saying, “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.”

The President added, “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. 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 reiterated, “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.”

However, he said, the US “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.”

Putin, Biden said, has reacted as though someone has threatened Russia – although the US president says no one has. The President concluded with an entreaty; “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. And we still believe by working together we can bend the arc of history toward a freer and more just world for our children. 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,”

Whether the conflict will turn into an open nuclear competition is uncertain. Still, Putin is eager to flex his muscle and keep people on their toes after a stunning series of effective push-backs from embattled Ukraine forces over the past week.