Biden warns Putin's 'back is against the wall' in Ukraine and says the Russian president may be considering using biological or chemical weapons

• Biden said Putin may be considering using biological or chemical weapons in Ukraine.
• "His back is against the wall," he said. "That's a clear sign he's considering using both of those."

President Joe Biden said Russian President Vladimir Putin may consider using chemical or biological weapons in Ukraine as his military struggled to achieve clear objectives.

The White House said earlier this month that Putin had made false claims that both the US and Ukraine had biological and chemical weapons — allegations Biden denied at the Business Roundtable's CEO quarterly meeting in Washington, DC, on Monday.

"His back is against the wall," Biden said. "That's a clear sign he's considering using both of those."

He added: "He's already used chemical weapons in the past, and we should we careful of what's about to come."

Biden also said he believed Russia may deploy cyberattacks against the US and urged the private sector to bolster its cyberdefenses.

Since Russia invaded Ukraine nearly four weeks ago, Western officials have expressed concern that Putin is manufacturing a pretext to justify using chemical and biological weapons in Ukraine.

Biden previously vowed that Putin would suffer consequences if he deployed chemical weapons against Ukrainians.

"I'm not going to speak about the intelligence, but Russia would pay a severe price if it used chemical weapons," Biden said at the White House earlier this month.

Chemical and biological weapons were banned under the Geneva Protocol after World War I.

After the collapse of the Soviet Union, Russia was supposed to destroy its stockpile of chemical weapons, though the US and experts believe the country still holds on to a secretive supply. The Kremlin previously denied it would launch a chemical weapons attack on Ukrainians.

Meanwhile, Russia's advance on Ukraine has appeared to be largely stalled across all fronts as Putin's forces struggle to achieve its military objectives — including capturing the Ukrainian capital of Kyiv.

Russian forces have ramped up their assault on Ukrainian cities and hit shelters and a maternity hospital.

The war has forced a devastating refugee crisis in which over 10 million Ukrainians have been displaced from their homes, with millions flooding across the border and into neighboring countries.