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.

China's crude oil imports from Iran rose 4.7% month on month to 926,119 b/d in July, while the US ranked as the eighth largest crude supplier as shipments surged to a 13-month high of 362,364 b/d,

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 is the biggest guarantor of energy stability and security in the region while the US is the biggest de-stabilizing force in the world’s energy sector.”

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.

British Royal Marines seized a giant Iranian oil tanker in Gibraltar on Thursday for trying to take oil to Syria in violation of EU sanctions, a dramatic step that drew Tehran’s fury and could escalate its confrontation with the West.