The alliance protects the interests of its members and their merchant ships when passing through maritime corridors. Its operation area covers the Strait of Hormuz, Bab Al Mandab, the Sea of Oman and the Arabian Gulf.

Iranian Minister of Petroleum Bijan Zangeneh stressed the non-political nature of oil, saying the US was using oil as a weapon which was not the right approach.

The US made another request to import-dependent Japan to join the coalition, and leaders are expected to discuss it at the UN General Assembly in New York next week.

The United States will continue to impose sanctions on whoever purchases Iran’s oil or conducts business with Iran’s Revolutionary Guards and no oil waivers will be re-issued, a U.S. official said on Sunday.

President Hassan Rouhani has stressed Iran's determination to take the third step towards reducing Iran’s obligations to the Joint Comprehensive of Plan of Action(JCPOA)

“Iran has repeatedly stated that it will resume full implementation of its commitments to the JCPOA only when it can freely sell its oil and fully access its oil revenues. France’s initiative is exactly about this issue,” Araghchi said.

The US has said it intend to bring Iran's oil exports down to zero. In July Iranian crude and condensates exports totaled around 450,000 b/d, which was less than half of the May export figure of 910,000 b/d,

Brian Hook, the U.S. special envoy for Iran, said Wednesday that the U.S. will “continue to drive up the costs” for Tehran’s efforts to develop ballistic missiles and take other actions soon after the Treasury Department imposed new restrictions on a shipping network controlled by Iran’s Islamic Revolutionary Guard Corps.

"Western sanctions have helped deepen Russia-China energy links as Chinese entities have emerged as a source of capital, which in turn has facilitated Chinese financing of the Yamal LNG project as well as the conclusion of the Power of Siberia pipeline," Dr Michal Meidan, director of the China Energy Program at the Oxford Institute for Energy Studies, said.

Foremost among the areas to be patrolled is the Strait of Hormuz, between Oman and Iran, through which about one-fifth of the world’s seaborne crude flows out of the Gulf.

The UK's Royal Navy will work with the US to assure the security of merchant vessels in the Strait of Hormuz, the Ministry of Defence said.

"I think Iran will look at it as a successful cost imposition to the adversary," "They're making all of the adversaries now rally forces, move them into the theater, put them at risk in the theater and pay for that presence at a very hefty price."

"We are committed to keeping the Strait of Hormuz open and secure," Pompeo said.

European signatories to the Iran nuclear deal do not see Tehran's recent moves reducing compliance as significant and do not intend "for now" to trigger the agreement's dispute mechanism

Iran said on Sunday it will shortly boost its uranium enrichment above a cap set by a landmark 2015 nuclear deal, prompting a warning ‘to be careful’ from U.S. President Donald Trump, who has pressured Tehran to renegotiate the pact.