The threat of Russian President Vladimir Putin using nuclear weapons in Ukraine was warned by the CIA Director on Thursday.

Given the potential desperation of President Putin and the Russian leadership, no one can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons.

Russia has struggled to make gains on the ground since launching a war in Ukraine. Russia has lost thousands of soldiers and many generals have been killed. The flagship of the Russian Black Sea fleet, the missile cruiser Moskva, was lost recently.

Experts have expressed grave concerns that Putin could use weapons of mass destruction as he feels backed into a corner. After the war began, Putin ordered Russia's nuclear deterrent forces to be on high alert. NATO Secretary General Jens Stoltenberg decried Russia for its nuclear saber-rattling.

We are obviously very concerned. Burns, a former US ambassador to Russia, said Thursday that President Biden is concerned about avoiding a third world war and avoiding a threshold in which nuclear conflict becomes possible.

In a new interview with CNN, the Ukrainian President said the world needs to be ready for the possibility of Russia using nuclear weapons in Ukraine.

Tactical nuclear weapons are usually less powerful than strategic nuclear weapons, and have lower blasts designed for use against military positions. That can make their use more appealing.

Tactical nuclear weapons exist because both sides fear they will be used to destroy big city. The use of nuclear weapons becomes more thinkable by making them smaller and more precise. Paradoxically, while this makes deterrence threats more credible, it also makes the arms more tempting to use first, rather than simply in retaliation, according to a political scientist at Brown University.

It is worrisome that the war could lead to the use of nuclear weapons. By increasing the alert level of Russian nuclear forces, Putin increases the risk of nuclear use.

Ivo Daalder, the former US Ambassador to NATO, told Insider that the US and NATO should help the Ukrainians and beat the Russians if they use weapons of mass destruction.

He said that they couldn't stand by as Russia decided that it would use chemical warfare or a nuclear weapon.

The Biden administration has provided billions of dollars in military assistance to the Ukrainians, but has made it clear that US troops will not be sent to fight Russia. In March, Biden said the US and NATO would respond if Putin used chemical weapons in Ukraine, and the White House has set up a team to develop contingency plans.

The US and its allies launched investigations over reports that Russia used chemical weapons in the besieged port city of Mariupol.