Former NATO Supreme Allied Commander retired U.S. Navy Admiral James Stavridis said Sunday that Moscow would be abandoned by its allies—including Iran and China—if Russian President Vladimir Putin used a nuclear weapon on Ukraine.

Stavridis' comments came after the Russian leader issued a nuclear threat over Ukraine in a televised speech to his country last week.

"If Russia feels its territorial integrity is threatened, we will use all defense methods at our disposal, and this is not a bluff," Putin said. "Those who are trying to blackmail us with nuclear weapons should know that the winds can also turn in their direction."

Soon after the start of his invasion of Ukraine in late February, Putin put his nuclear forces on high alert. For months, Russian-state television has been framing the war as a battle between the West and Russia, whose goals could be expedited if the Kremlin drew on its estimated 6,000 warheads.

Putin Would Abandoned if it Uses Nukes
Above, Russian President Vladimir Putin gives a speech on September 21. Former NATO Supreme Allied Commander James Stavridis said Sunday that Russia would be abandoned by its allies—including Iran and China—if Russian President Vladimir Putin used a nuclear weapon on Ukraine. Ilya Pitalev

In an interview on WABC 770's Cats Roundtable, Stavridis said that Putin "does not seriously contemplate using a nuclear weapon."

"He knows if he did, it would cause the world entirely to turn against him. He would even lose the support of the Chinese, the Iranians. No one is going to support a Russia that uses nuclear weapons. So, I don't take that seriously," he added.

Newsweek has reached out to the Russian Foreign Ministry for comment.

Last week, former Russian Prime Minister Mikhail Kasyanov told Newsweek that he also believes that the Russian leader's nuclear threat is an empty one.

"He has tried to make people scared because of the use of nuclear weapons, but I think this is in the category of a bluff," Kasyanov said. "I don't think he will turn to a nuclear weapon for the simple reason that he realizes he himself would be immediately eliminated."

'No One Wants to Be Drafted'

In his Sunday interview, Stavridis also talked about the "partial mobilization" effort Putin announced last week. With the mobilization, the Russian military will call up to 300,000 reservists, who have some military training, to fight in Ukraine. The development has led to protests and mass arrests around the country.

"[Putin's] biggest problem is his troops being killed. He's lost about 80,000. Now he needs to replace them," Stavridis said. "The problem for him...is that no one wants to be drafted. There are major protests popping up in Russian cities. It's starting to have that Vietnam-era feel of a growing sense of civil discontent. So, I would score it a very bad week for Vladimir Putin."

In an interview in August, Stavridis said he believes Putin knows he's made a mistake with his invasion of Ukraine.

"I think in the dark, quiet hours at two o'clock in the morning when he wakes up, he realizes he's made a mistake. Publicly, he'll never at admit that. Never. He'll continue to maintain this fiction that Ukraine is run by 'neo-Nazis.' Ridiculous, obviously," Stavridis said.

U.S. Officials Communicate With Moscow About the Use of Nuclear Weapons

National security adviser Jake Sullivan said Sunday that U.S. officials have communicated to the Russians that there will be "catastrophic consequences for Russia if they use nuclear weapons in Ukraine."

"We have communicated directly, privately to the Russians at very high levels that there will be catastrophic consequences for Russia if they use nuclear weapons in Ukraine. We have been clear with them and emphatic with them that the United States will respond decisively alongside our allies and partners," Sullivan said on ABC's This Week, adding that the Russians "well understand what they would face if they went down that dark road."