Iran warned Britain's next prime minister Boris Johnson on Tuesday that it will "protect" waters of the oil-rich Gulf, amid a standoff between the two countries over the seizure of tankers.
In the face of rising hostilities with the United States, Iran's Islamic Revolutionary Guard Corps on Friday impounded a tanker sailing under the flag of US ally Britain.
The seizure of the Stena Impero ship has been seen as a tit-for-tat move after British authorities detained an Iranian tanker on July 4 in the Mediterranean on suspicion it was shipping oil to Syria in breach of EU sanctions.
"I congratulate my former counterpart, @BorisJohnson on becoming UK PM," Iranian Foreign Minister Mohammad Javad Zarif tweeted after Johnson beat his rival, Foreign Secretary Jeremy Hunt, in a party vote.
"Iran does not seek confrontation. But we have 1500 miles of Persian Gulf coastline. These are our waters & we will protect them."