Former White House National Security Adviser H.R. McMaster told CBS News on Monday that Russia’s attacks on supply lines in Ukraine — and its claims about chemical weapons — are a "sign of weakness" that shows the country is "desperate."

McMaster, who recently joined CBS News as a contributor on foreign policy and national security, noted, "What you're seeing is that Russia is really getting desperate — not only with this action to try to interdict the supply routes but also with trying to lay the groundwork for, maybe, the use of chemical weapons, which is concerning."

He also said Russia will make any attempt to interfere with humanitarian assistance to Ukraine, including attempting to intercept supplies and military equipment en route to the country.

McMaster went on to say that Russia’s claims during a United Nations Security Council meeting last week, where it said that the U.S. was conducting "military biological activities" in Ukraine, was a "false flag effort" on the part of Russia.

"This is a real sign of weakness," McMaster told CBS News. "I think Russia — and Putin, in particular — is in real trouble."

He went on to say that talk about escalating the invasion into World War III "kind of plays into [Russian President Vladimir] Putin's hand. What he's trying to do is to threaten an escalation of the war so that we will throttle back on our support for Ukraine."

McMaster also said that China should be doing more to condemn the invasion and that the West should take advantage of the nation's lack of action.

"What China's been doing is providing cover for Russia's mass murder of innocent civilians, spouting the same narrative that this isn't really a war, calling it a 'special military operation,' [and] also supporting these false claims of military bio-labs in Ukraine," he said. "And I think it's a tremendous moment for the free world to shift the balance back in favor of the free world and away from these two authoritarian dictatorships.”

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