US Defense Secretary Mark Esper said Saturday he was "not surprised" Iran had turned on advanced centrifuges to increase uranium stockpiles, a further breach of the 2015 nuclear deal which Washington pulled out of last year.
"I'm not surprised that Iran has announced that it's going to violate the JCPOA," Esper said in Paris, using the official name of the accord signed in Vienna four years ago.
"They had been violating it, they had violated the nuclear non-proliferation treaty for many years, so it's no surprise that the Iranians are going to pursue what the Iranians have always intended to pursue," he added, following talks with his French counterpart Florence Parly.
Esper was in France after visits to London and Stuttgart, Germany, to meet with NATO allies since taking up his post in July.
Parly reiterated France's calls for Tehran to "respect the Vienna accord", adding "we will continue with all our diplomatic efforts in this direction. We have to continue."
France and other EU nations have been trying to ease tensions in the Gulf region since President Donald Trump abandoned the nuclear deal and re-imposed sanctions that have hit the Iranian economy hard.
President Emmanuel Macron has overseen recent talks between French and Iranian officials, and even secured a potential opening with Trump at last month's G7 summit, when he said he would be willing to meet with Iran's President Hassan Rouhani.
Esper said he had "productive discussions" with Parly, though neither indicated any progress had been made on de-escalating the conflict.
They also agreed to disagree on the US's new "maritime security mission" in the Gulf, aimed at ensuring open passage for vessels through the Strait of Hormuz after a series of incidents, including ship seizures by Iranian forces.
France has declined to join the US initiative and instead sought out like-minded partners for its own surveillance of the strategic waterway.
"The goal is to rally as many partners and means of surveillance as possible to improve security in the Gulf, and there's absolutely no competition between these initiatives," Parly said.
Esper said the US effort "is about deterring bad behaviour."
"Obviously our preference is that all countries join underneath this broader umbrella," he said.
Esper reiterated that China along with Russia were the main threats as the US shapes its defence strategy for the coming years, and warned Europe about its own vulnerabilities to the two countries as well.
"China is seeking to gain influence around the world and throughout Europe, in many ways contrary to the interests of European states," he said.
Yet the prospect of huge Chinese spending has opened doors to Beijing across the Indo-Pacific region and into Africa, with Italy also recently accepting billions of euros from China for a major port expansion.
"As countries increase their dependence on Chinese investment and trade, they become more susceptible to coercion and retribution when they act outside of Beijing's wishes," Esper said.
But he declined to confirm if the US defence shift toward China and Russia would lead to fewer American troops in Africa, where France is leading efforts against Islamic terrorist groups operating across large swaths of sub-Saharan territory.
"I've not made any decisions," Esper said. "I'm looking at every theatre, and every command, to figure out how I can economise our forces, how I can optimise our assets."
He praised France's role, saying its was "directly benefiting the security of Europe," and revealing that "earlier this week our French partners provided a lifesaving medical evacuation for a US soldier in Africa."
Analysts have speculated the US may shift to a drone-based presence for Africa, and France has often sought American surveillance and drone strikes for operations by its 4,500-strong Barkhane counter-insurgency force.