A nuclear war with Russia may be "just a few steps away" due to bristling tensions with the West over Ukraine said an RAF chief, while the situation is made worse by fears China could provide military support to Russia.
US national security adviser Jake Sullivan has raised concerns about China's alignment with Russia in a seven-hour meeting with Chinese diplomat Yang Jiechi.
It comes as Washington warned of the isolation and penalties Beijing faces if it helps Moscow in Ukraine.
RAF Air Marshal Edward Stringer CBE issued the stark warning that World War Three could very easily be triggered in Ukraine which would involve nuclear weapons.
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It follows Lord West also having said previously that nuclear war could be sparked by a single wrong move.
Now, Stringer believes that the possibility of this will be "weighing on the minds" of world leaders.
He told LBC: "It's no longer unthinkable and it will clearly be weighing on the minds of those who are making all the political calculations at the moment, hence the very straight and consistent line from Biden and all the other senior heads of state recently.
"It's in the realms of possibility, and that's what people have to get their heads around."
Stringer went on to say you could "sketch a plausible chain of events" that may cause a nuclear war, which is "only a few steps to get from where we are now".
"That's only a few steps to get from where we are now to a confrontation that could see the use of nuclear weapons, which I think is a pretty terrifying prospect for anybody sensible," he added.
President Vladimir Putin has continuously threatened the West with "untold consequences" if Russia is confronted over Ukraine.
Stringer's warning comes just one day after Russia shared a clip of its 7,000mph Zircon hypersonic nuclear missile being fired from the Admiral Gorshkov frigate in the White Sea.
The missile could strike London within minutes.
Meanwhile, the meeting between US national security adviser Sullivan and Chinese diplomat Yang took place in Rome as Washington told allies in NATO and several Asian countries that China had signalled its willingness to provide military and economic aid to Russia to support its war, two US officials said.
The US message, sent in a diplomatic cable, also noted China was expected to deny those plans, said one of the officials, speaking on condition of anonymity.
"It's real, it's consequential, and it's really alarming," the second US official said, although the US government offered no public evidence to back its assertions of China's willingness to provide such aid to Russia.
After talks ended, the White House issued a short statement, saying Sullivan raised a "range of issues in US-China relations, with substantial discussion of Russia's war against Ukraine."
"We have deep concerns about China's alignment with Russia at this time, and the national security adviser was direct about those concerns and the potential implications and consequences of certain actions," a senior administration official told reporters.