Bill Ackman, founder and CEO of Pershing Square Capital Management.Bill Ackman, founder and CEO of Pershing Square Capital Management.

Bill Ackman, a billionaire hedge fund manager, has warned that World War III is likely to start already.

In January 2020, I had a lot of nightmares about the potential for a pandemic, but everyone thought I was crazy. I am having similar nightmares now, said Ackman in a late Saturday message.

In early 2020, when less than 7,000 coronaviruses cases had been confirmed in the U.S., Ackman called for a 30-day national lockdown and warned thathell is coming.

After his fund made more than $2 billion on bets against the markets, Ackman defended his comments.

On Saturday, Ackman said that WWIII has likely started already, but we have been slow to recognize it.

The U.S. could stop buying oil from Russia and funding the war if demand for gas goes down in the spring.

EU officials are set to discuss proposals for ending the bloc's reliance on Russian fossil fuels on Tuesday, with the Ukrainian President issuing a call for an international boycott of Russian oil on Monday.

The prospect of a Russian oil embargo sent international benchmark crude futures to 13-year highs on Monday.

NATO members would be able to assist Ukraine without putting troops on the ground if they were supplied with the West's best weaponry, intelligence and drones.

The Ukrainians have what it takes to win the war, unless and until Putin goes nuclear, he said.

He said that the West provoked Putin by giving the Ukrainians weapons that they were able to use against Russia.

A lot of countries around the world have given money and weapons to the country to help it defend itself against the Russians. The US has asked Congress to approve billions of dollars in funding for Ukraine since Russia launched its attack on February 24.

Ackman argued that NATO's reluctance to intervene due to the nuclear threat posed by Russia was a poor strategic move.

The nuclear threat is the same when he takes his next country, whether it is part of NATO or not.

Last week, Putin put Russia's nuclear deterrence forces on high alert, saying it was a defensive response to Western condemnation of his invasion of Ukraine, and warning that any country that tried to interfere would suffer consequences unseen before in history.

During Russia's previous invasion campaigns, Ackman said, we did nothing to stop Putin.

Russian forces invaded neighboring Georgia in 2008, a move that saw an informal invitation for further acts of aggression in Russia's traditional sphere of influence. In the year of 2014, Russia annexed the peninsula of Crimea.

According to Ackman, we are in the early stages of Putin's global ambitions.

He is testing us, and we are failing the test each time.

Biden, NATO Chief Jens Stoltenberg and the Prime Minister of the United Kingdom all ruled out putting troops on the ground or establishing a no-fly zone above the conflict in eastern Ukraine.

Biden has said that the U.S. and its allies would defend all of NATO's territory.

Setting a hard line based on NATO membership doesn't give Putin carte blanche to invade and subjugate Sweden, Finland, Cyprus, Ireland, Austria, Malta, and Switzerland, and the rest of the former Soviet Union.

The only way to deter Russia from attacking more countries was for the West to give the Ukrainians every weapon it had, according to Ackman.

NATO should re-consider enforcing a no-fly zone over Ukraine if sanctions failed to have an impact on Putin's actions.

The key to ending the crisis in Ukraine was argued by Ackman.

The only way I can see out of this war is for China to broker a real ceasefire and a settlement, he said. Russia can withdraw and the sanctions can be reversed.

Putin respects and fears China, according to Ackman. Time is running out for many 18-month-old children.

China, an economic and strategic ally of Moscow, has not imposed any sanctions on Russia. Beijing called for an end to the hostilities in Ukraine.

Stephen Roach, an economist with CNBC, said on Monday that China is holding the trump card in the pursuit of a peace deal with Russia.

Roach said that there was only one person in the world who had leverage over Putin.

The story has been changed to reflect that Ackman posted on the correct day.