The rift between the United States and Russia is approaching a possible flashpoint as the former Cold War enemies tussle over cyber warfare threats, nuclear missile treaties and their ever-escalating Syrian “proxy war”.

An alarming warning from flamboyant Russian politician Vladimir Zhironovsky – who is close to Mr Putin – who on Thursday warned of a nuclear war should Donald Trump not become US president.

“Relations between Russia and the United States can’t get any worse. The only way they can get worse is if a war starts,” Zhirinovsky told Reuters.

“Americans voting for a president on November 8 must realise that they are voting for peace on planet Earth if they vote for Trump,” he said.

“But if they vote for Hillary [Clinton] it’s war. It will be a short movie. There will be Hiroshimas and Nagasakis everywhere.”

Many experts and officials are now of the opinion that the military giants are a step closer to war, while others say the pair are already engaged in a war thanks to the Syrian conflict.

Speculation of a breakdown in relations was rife this week after Russian President Vladimir Putin reportedly called on all foreign Russian diplomats, their families, as well as prominent countrymen abroad, to return home.

Some experts have disputed this translation of the report, saying that Putin’s statement was a request, not an order, and that it was an issue of domestic image rather than threat of war.

According to the latter interpretation, Putin feels that it is inappropriate for Russia’s upper class to be sending their children to foreign Western schools while the motherland is clashing with the US and its allies.

Curtin University Russian affairs watcher Alex Muraviev told The New Daily that if Russia and the US were to engage in warfare, it would almost certainly involve nuclear weapons.

“Any open military conflict between Russia and the United States would most likely escalate to an open nuclear confrontation where there are no winners,” Mr Muraviev said.

“The war in Syria is a proxy war. There is no doubt about that. It is a proxy war between Russia and the United States using proxy allies on the ground.”

Vladimir Putin has caused controversy with his support for Bashar al Assad’s Syrian regime. Photo: Getty

Those proxy allies are, for Russia, the Syrian regime led by President Bashar al Assad and for the US, rebels that want Mr al Assad booted from power.

Both military giants in Syria are trying to simultaneously destroy Islamic State, via very different approaches.

‘This is a conflict’

Senior US-Russia relations expert Matthew Rojansky told CNN that the conflict had already begun.

“This is a conflict, there should be no doubt,” Mr Rojansky said.

On Wednesday (AEDT), White House press secretary Josh Earnest said a “range” of “proportional” reactions to the alleged Russian hacking of US political groups was being considered.

Donald Trump has done business in Russia before, despite denying it. Photo: Getty

This came after numerous leaks of Democratic Party emails, attacks that are reportedly originating from Russia.

Moscow denied the allegations through its foreign minister Sergei Lavrov, who said his nation was “flattered” by the claims.

Democratic presidential candidate Hillary Clinton has accused Russia of conducting the hacks to help Republican candidate Donald Trump to the presidency.

Earlier this month, Russia left a nuclear security pact struck in 2000 citing the US’s inability to honour its side of the deal.

According to French news agency AFP, this led former Soviet Union leader Mikhail Gorbachev on Tuesday to beg for the nations to work to resolve the tensions.

“I think the world has reached a dangerous point,” Mr Gorbachev was quoted as saying.

“This needs to stop. We need to renew dialogue.”

Mr Putin and Mr al-Assad’s friendship has been causing a lot of tension in the Syrian conflict. Photo: Getty

Mr Gorbachev was addressing the fact that the US and Russia called off their dialogue in the Syria conflict.

On Tuesday Mr Putin cancelled a trip to France after French president Francois Hollande said he was reluctant to meet with the Russian leader.

Mr Hollande’s remark was in response to Russia blocking a French-sponsored effort to impose a no-fly zone over the Syrian city of Aleppo at the UN.

In late September and early October, Russia held civil defence drills for 40 million citizens amid claims there were nuclear bunkers under Moscow to accommodate all 12 million residents, according to reports.

In April, two Russian warplanes flew aggressively close to a US warship in the Baltic Sea. The US military called it a “simulated attack”.