WASHINGTON, DC -- Armed attack boats believed to belong to Iran's Islamic Revolutionary Guard Corps (IRGC) attempted to seize a British tanker in strategic Gulf waters Wednesday (July 10) but were driven off by a Royal Navy frigate.
"Three Iranian vessels attempted to impede the passage of a commercial vessel, British Heritage, through the Strait of Hormuz," said the UK Defence Ministry.
The Iranians ordered the tanker to change course and stop in nearby Iranian waters, CNN said, citing two American officials.
A US aircraft shot video of the incident, which ended when the HMS Montrose -- which was escorting the tanker -- trained its guns on the boats and successfully warned them to back off, according to CNN.
The IRGC, which was designated as a terrorist organisation in April following decades of hostile acts worldwide, denied trying to seize or impede the UK tanker.
"There has been no confrontation in the last 24 hours with any foreign vessels, including British ones," the Revolutionary Guards said in a statement.
The denial, however, rings hollow in light of recent threats the Iranian regime has made against the United Kingdom.
The IRGC said Thursday (July 11) that the United States and United Kingdom would "strongly regret" the detention of an Iranian tanker off Gibraltar late last week, the semi-official Fars News Agency reported.
Gibraltar officials said that the cargo was believed to be destined for Syria, which is subject to European sanctions. The tanker was halted by Gibraltar's police, aided by British Royal Marines.
"If the enemy had made the smallest assessment, it wouldn't have done this act," said Rear Adm. Ali Fadavi, deputy commander in chief of the Revolutionary Guards.
Iranian President Hassan Rouhani warned the United Kingdom Wednesday of the "consequences" of what he described as "a foolish act".
"I point out to the British that you initiated insecurity [on the seas] and you shall grasp the consequences of it later on," Rouhani said in comments to the cabinet broadcast by state TV.
On Monday (July 8), Iranian Defence Minister Brig. Gen. Amir Hatami vowed to respond to the United Kingdom's move, which he called an act of maritime piracy.
The seizure "will not be tolerated by us", he said.
If the United Kingdom fails to release the tanker, Iran will be forced to take tit-for-tat action, warned Mohsen Rezai, the secretary of Iran's Expediency Council, a key advisory and arbitration body, warned.
"If Britain does not release the Iranian oil tanker, the relevant authorities will be duty-bound to take reciprocal action and seize a British oil tanker," he said.
The incident comes as the United States is hoping to build a coalition to present a united front against intensifying threats from the Iranian regime.
The United States will take the commanding role and provide surveillance as other countries escort vessels under their own flags, said Gen. Joseph Dunford, the top US military officer.
"I think probably over the next couple weeks we'll identify which nations have the political will to support that initiative, and then we'll work directly with the militaries to identify the specific capabilities that'll support that," Dunford said Tuesday (July 9).
The coalition will operate both in the Strait of Hormuz -- the choke-point to the Gulf through which 20% of the world's oil flows -- and the Bab el-Mandeb, the crucial shipping line into the Red Sea off war-battered Yemen, he said.
"Threats to international freedom of navigation require an international solution. The world economy depends on the free flow of commerce, and it is incumbent on all nations to protect and preserve this linchpin of global prosperity," said Capt. Bill Urban, lead spokesman of US Central Command, on Thursday.
The budding coalition comes amid heightened tensions after Iranian forces shot down a US drone over international waters and attacked several oil tankers near the Strait of Hormuz.
In response, concerned nations requested an emergency meeting of the International Atomic Energy Agency (IAEA).
The Iranian regime is engaged in "nuclear extortion", US Ambassador to the IAEA Jackie Wolcott told the meeting.
Tehran has said it will disregard certain limits under the deal as long as the remaining parties to the deal -- in particular the United Kingdom, France and Germany -- do not do more to mitigate the impact of US sanctions.
"There is no way to read this as anything other than a crude and transparent attempt to extort payments from the international community," Wolcott said.