The former head of the US Central Intelligence Agency has been accused of “siding with Iranian zealots” – after he labelled the assassination of a top Iranian nuclear scientist as a “criminal act” and “state-sponsored terrorism.”

In a series of tweets, John Brennan – who served as CIA chief for four years under Barack Obama – said the roadside ambush of Mohsen Fakhrizadeh was “highly reckless” and risked “lethal retaliation” and “a new round of regional conflict.”

Fakhrizadeh was long said by the West to head Iran’s military nuclear program – but, as Mr Brennan pointed out, he wasn’t a member of a designated terrorist group that would be a legal target. Such groups would include Islamic State or Al Qaeda.

Tweet from @JohnBrennan

Brennan – a fierce critic of the Trump administration – went further by calling on Tehran to hold fire, both literally and politically, and wait for Mr Trump to leave the White House before even communicating with the US.

He essentially urged the  Iran leadership to wait and deal with Joe Biden:

“Iranian leaders would be wise to wait for the return of responsible American leadership on the global stage & to resist the urge to respond against perceived culprits.”

Tweet from @JohnBrennan

Texas Senator Ted Cruz tweeted in reply:

“It’s bizarre to see a former head of the CIA consistently side with Iranian zealots who chant Death to America… Does Joe Biden agree?’

Mr Cruz later said that Brennan had violated the Logan Act, a 1799 law that prohibits unauthorized American citizens from interfering in disputes or controversies between the United States and foreign governments.

Predictably, there was a partisan Twitter pile-on, with many on the Left concerned that the killing could lead to war. Those on the Right accused Brennan of treason and selling out.

One Willem B Hook warned Brennan: “Treason is punishable by death John”.

One more confusing element to one big mess

The Brennan-Cruz exchange is a sideshow in a complicated and potentially catastrophic situation.

At the moment, the assassination of Fakhrizadeh is assumed to be the work of Israel. For one, thing, the killing itself has a commando-like feel about it. A truck loaded with explosives went up in smoke as Fakhrizadeh’s car made its approach.

John Brennan has been a staunch critic of Donald Trump. He says the killing of an Iran nuclear scientist could lead to escalated conflict in the region. Photo: Getty

This apparently was a strategy to take out at least some of Fakhrizadeh’s bodyguards. Gunmen then emerged to shoot the scientists dead. That this occurred near a town frequented by Iran’s elites was both brazen – and it also sent a warning that anyone in the regime’s upper echelon is vulnerable.

But the killing comes just two weeks after President Trump was talked out of launching a missile attack on Iran, and it’s assumed that the US and Saudi Arabia were aware of the impending attack, and may have had a hand in its planning.

Meanwhile, Joe Biden has made plain that he wants to resurrect the  2015 nuclear deal that was struck between Iran and a group of world powers  known as the P5+1. These included the US, UK, France, China, Russia and Germany.

The deal, known as the Joint Comprehensive Plan of Action – and regarded as Barack Obama’s signature foreign policy achievement bvy his admirers– was meant to end years of tension over Iran’s alleged efforts to develop a nuclear weapon. Iran insisted that its nuclear program was entirely peaceful, but the international community did not believe that.

Kylie-Moore Gilbert. She arrived home in Australia around the time of the assassination. A day later and she’d still be behind bars in Iran.

The deal saw Iran agree to limit its sensitive nuclear activities under the eye of international inspectors – in return, crippling economic sanctions would be lifted.

Donald Trump eventually skittled the deal, in part to break away from America’s European allies.

Hence, this killing is seen, in part, as a way of sabotaging the incoming Biden administration’s push to return normality to NATO, and to put a lid on Iran’s hot temper.

If war broke out between the US and Iran, Australia would be almost automatically dragged into it. One awkward issue here: the US is very fond of our elite SAS soldiers, now under investigation for dozens of unlawful killings.

If there’s a clear winner here, it would be Melbourne academic Kylie Moore-Gilbert – who has spent a miserable two years in an Iranian prison on espionage charges. She was airlifted out of Iran and returned home just as the assassination was taking place.

Another day later and she might still be behind bars.