Abu Dhabi (CNN) In the not very complicated mystery over the attacks on oil tankers in the Gulf of Oman, there are two prime suspects with motives for the crimes. Only one, however, stands to benefit, whoever is responsible.

Iran.

It's no surprise that Tehran has now announced an increase in the production of low-enriched uranium. Both moves help Iran's rulers turn a gap between the US and its most powerful allies in Europe into, well, a gulf.

They also drive home the point that, whatever the US (and its allies in Saudi Arabia and Israel) may think, heavy economic pressure on Iran can have dangerous consequences.

There is already dismay in European capitals at the US' unilateral withdrawal from the international agreement that committed Iran to stalling any alleged development of nuclear weapons.

The deal was signed in 2015 by Russia, France, the UK, China, Germany and the US. Only the US, under President Donald Trump, walked away from it -- even though all parties agreed that Iran was meeting its obligations under the deal.

Iran is still complying with its obligations under the deal, but has threatened to up its production of nuclear materials past the compliance threshold by the end of the month.

So, the Europeans have until then to somehow bring the US around to the idea that it may be worth dialing down the scale of sanctions and restarting talks with Iran.

On receiving the new credentials of the French ambassador to Iran, President Hassan Rouhani warned "France and the rest of the members of the nuclear deal, have a very small chance to fulfill their historic obligation to keep the deal. The collapse of the Iran deal is not in the interests of Iran, France or the rest of the world," according to Iran's semi-official Fars news agency.

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The collapse of the deal risks more US sanctions on Iran -- or some kind of military action by the US against Iran's nuclear industry (at least).

And if that's what the future holds, the alleged mine attacks in the Gulf are a warning.

The other countries, or alliance, with a motive for bombing the ships in the Gulf are the US and Israel, according to Iranian officials. Given that the US National Security Advisor, John Bolton, has personally called for regime change -- and given that the US and UK governments lied their way to war in Iraq some 16 years ago -- they say it's not inconceivable that the Gulf attacks are a "false flag" black operation intended to generate a casus bellum.

But the reality is -- and Iran knows this as well as the US -- that a war against Iran would be catastrophic. US forces are no where near powerful enough in the region to contemplate a conventional war -- still less to cope with the asymmetrical conflict that would, the Iranians have warned, involve pro-Tehran militia in attacks against the US and her allies from Saudi Arabia to Israel and Iraq.

So a US motive is there -- but an unlikely scenario.

The US, Saudi Arabia, and the UK are all adamant that it was Iranian forces who somehow planted magnetic mines to the hulls of moving ships and blew them up. And it was done so skillfully that not a drop of oil was spilled.

The US is dispatching 1,000 troops to the region after the US Navy filmed the removal of what they said was an unexploded limpet mine from the hull of one of the stricken ships by the Iranian navy. Photographs released by the US of damage to the Kokuka Courageous were used to reinforce the allegations that Iran was behind the attacks.

Accepting that the Iranians committed the crime means accepting its motives for the act -- and that it may re-offend.

If Iran is responsible, the motive is clear: to safely signal to the world that it's very angry at recent punitive US sanctions which have throttled its oil exports and crippled its economy; to further signal that it can do economic damage to America's allies in Saudi Arabia and the rest of the Gulf, who export about a third of the world's oil through a narrow 21-mile-wide channel; and to serve notice that it can pinch the throat of Hormuz at any time.

Ship owners are already facing an increase in insurance premiums to get through the Strait, and are being advised by US and British naval commanders to follow routes as far away from the Iranian coast as possible.

Ironically, in denying any Iranian role in the mine attacks, Iran's armed forces chief of staff spelled out his country's military capability.

"If the Islamic Republic of Iran wanted to block the export of oil through the Persian Gulf, it can do that BY force and in public," he said.

Bahrain, Kuwait, Oman, Qatar, the United Arab Emirates and Saudi Arabia are the EU's fourth largest export market.

Iran can't afford an economic conflict, much less a real war. And neither can anyone else. But in being blamed for a crime it's got the best motive to commit, it asks for Europe's help to remove its motive -- or risk worse to come.