That period between 1947 and 1991 featured several incidents where the world appeared to be teetering on the brink of Armageddon. While deeply concerning, he said, the standoff over Syria isn't anywhere near that level.

"There were so many different situations during the Cold War," said Giles, who is a a senior consulting fellow at London's Chatham House think tank. "There were periods of stability and periods of tension that were far worse than what we're experiencing now."

Trump's tweet suggested he believes the current tension to be worse than what's widely regarded to be the riskiest moment of the 20th century, the Cuban missile crisis of October 1962.

This was the only time during the Cold War when U.S. forces were placed on DEFCON 2, in what the State Department's Office of the Historian calls "the moment when the two superpowers came closest to nuclear conflict."

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While this was the most notorious near miss, it was far from the only one. In 1983, for example, a military drill carried out by the U.S. and its allies was so realistic that it convinced Soviet generals that a nuclear strike was imminent.

"I think that this is an enormous and rather characteristic amount of hyperbole from Donald Trump," said Justin Bronk, a research fellow at the Royal United Services Institute, referring to the latest outburst over Syria. "At times during the Cold War, we were literally minutes away at various points from all-out nuclear war."

So while it may be a stretch to couch the current standoff as the worst ever, some analysts do feel that Washington-Moscow ties may be at their lowest ebb for more than three decades.

President Ronald Reagan meets with Soviet leader Mikhail Gorbachev during a summit between the superpowers in Geneva on Nov. 21, 1985. AFP / Getty Images file

"Relations between leading Western countries and Russia are as bad as they have been since the early 1980s," according to Duncan Allan, a former official with the British Foreign Office who worked in the U.K.'s embassies in Moscow and Kiev.

The early 80s saw the Soviets shoot down a Korean airliner and NATO deploy more nuclear weapons to Western Europe. The appointment of Mikhail Gorbachev as Soviet leader in 1985 saw relations thaw.

Dmitri Trenin, the head of the Carnegie Moscow Centre and a former Soviet military officer, agreed that today's events are the worst since that time.

The US and Russia are now closer to a direct collision between their military forces than at any time since the Cold War. The only question on my mind: will Russia hit back at the US when it launches strikes against Damascus? — Dmitri Trenin (@DmitriTrenin) April 8, 2018

Nevertheless, all of the analysts who spoke with NBC News on Thursday said Trump's Cold War comparison was a limited and overly simplistic way of talking about a complex, modern theater like Syria.

Russia is a very different beast to the old Soviet Union. Its economy is smaller than Italy's and, like in the U.S., its arsenal of nuclear weapons is greatly reduced, although still enough to end the world many times over.

"We are not dealing with the USSR, we're not dealing with a superpower," said Allan, who is now an associate fellow at Chatham House. "The Russians won't thank you for saying that, but they are not a superpower comparable to the United States."

While some of the old threats may have diminished, new ones have arisen, for example cyberattacks and other forms of online meddling that Russia has been accused of deploying in recent years.

This doesn't mean that experts are blasé about the standoff over Syria.

It is still unclear what action Trump is planning to take in response to the chemical attack on a rebel enclave near Damascus over the weekend.

The president tweeted again Thursday pointing out that he "never said when an attack on Syria would take place. Could be very soon or not so soon at all!"

White House Press Secretary Sarah Sanders repeatedly told reporters that "all options are on the table."

The main concern is what will happen if the U.S. launches strikes on Syria and kills Russian personnel stationed there.

"What next? The day after the strike, we're going to have killed a lot of Russians," retired Gen. Barry McCaffrey said on MSNBC late Wednesday. "We're in a very complex, very dangerous situation."

The prospect of any sort of counterattack by Putin's forces means the U.S. and its allies will try to avoid hitting targets where Russians are based in Syria, Bronk at RUSI predicted.

This would also mean steering clear of Russia's feared S-400 air defense systems that are deployed there.

"I think it's enormously unlikely that Washington, London or Paris would prosecute targets where they thought there was a reasonable chance of Russians being killed," he said. "It's just too much of an escalation. I just don't think they'd do it."

One option might be to emulate last year's "pin prick" strike on Syria, in which the U.S. launched cruise missiles at a Syrian air base in retaliation for another chemical attack. The Pentagon warned Russia beforehand and the strike caused minimal damage.

"The problem with telling the Russians is they will, of course, tell the Syrians," Bronk said. "So the Syrians will move all the planes that they can within the time window. The strike would probably hit nothing, or at least very little."