Hours before the hijacking of the British oil tanker in the Persian Gulf, America’s special representative for Iran was explaining its position to diplomats in Washington. Some 100 envoys took part in the briefing by Brian Hook, who outlined the Trump administration’s initiative for maritime security in the Strait of Hormuz. Mr Hook said tensions had risen sharply and necessitated the need for a “coalition” of navies to protect their ships through the strait. His words were underlined by the seizure of the British-flagged Stena Impero in the Gulf. Elaborating on the plans, US Central Command described it on Friday night as “a multinational maritime effort”, called Operation Sentinel. “The goal of Operation Sentinel is to promote maritime stability, ensure safe passage, and de-escalate tensions in international waters throughout the Arabian Gulf, Strait of Hormuz, the Bab el-Mandeb Strait (BAM) and the Gulf of Oman. “This maritime security framework will enable nations to provide escort to their flagged vessels while taking advantage of the cooperation of participating nations for coordination and enhanced maritime domain awareness and surveillance.” The US had the day before been forced to down an Iranian drone that had flown too close to one of its navy ships. It could no longer sit idly by, he said. British oil tanker seized in the Gulf It was the first US military engagement with Iran after a series of increasingly serious incidents in the Gulf, and Donald Trump threatened more yesterday if Iranian planes flew too closely to its ships. Before the hijacking on Friday, a bizarre war of words broke out between the US and Iran after Tehran denied the president’s claim that one of its drones had been destroyed. “We have not lost any drone in the Strait of Hormuz nor anywhere else. I am worried that USS Boxer has shot down their own UAS [Unmanned Aerial System] by mistake,” Abbas Araqchi, Iran’s deputy foreign minister, responded in a tweet. Iran tensions | Read more Brig Gen Abolfazl Shekarchi added: “Despite Trump’s baseless and delusional claims, all of [Iran’s] drones … have safely returned to their bases.” The Revolutionary Guard released footage from what it said was the “downed drone”. State TV claimed the timing notations showed it was still filming after Washington said it had been put out of action. The US said it had its own “clear evidence”, but did not provide any. Mr Trump announced that the USS Boxer, an amphibious assault ship, “took defensive action” against the Iranian drone. “The US reserves the right to defend our personnel, our facilities and interests and calls upon all nations to condemn Iran’s attempts to disrupt freedom of navigation and global commerce,” he said. A journalist aboard USS Boxer suggested that Iran had been harassing the navy ship before the drone was shot down. Iran released footage from what it said was the “downed drone” Credit: AFP The reporter said an Iranian navy helicopter flew alongside them, yards from the deck, before it was chased away by a US helicopter. The convoy of six US warships passed several Iranian speedboats without incident, but was then tailed by a larger Iranian warship which came within 500 yards of Boxer. An Iranian Y-12 surveillance plane was then pursued by US helicopters before a surveillance drone came even closer and was then brought down by electronic warfare jamming. On Friday night, after reports that two British tankers had been intercepted, Bob Sanguinetti, chief executive of the UK’s Chamber of Shipping, said the escalation in tensions in one of the world’s most important chokepoints made it clear more protection for merchant vessels was urgently needed. He said the action was “in violation of international regulations which protect ships and their crews as they go about their legitimate business”.