A U.S. destroyer intercepted two oil tankers attempting to leave Iran on Tuesday and instructed them to reverse course, a U.S. official said, speaking on condition of anonymity. The action occurred a day after a U.S.-declared blockade began and followed the tankers' departure from Chabahar port on the Gulf of Oman.
The destroyer contacted the vessels by radio, the official said. It was not clear whether additional warnings were issued beyond that radio contact. The incident provides a concrete example of how the blockade has been enforced in its opening days.
U.S. Central Command, in a separate statement earlier on Tuesday, said six merchant vessels had complied with orders to "turn around to re-enter an Iranian port on the Gulf of Oman." Central Command added that no ships have passed the blockade since it went into effect on Monday at 10 a.m. in Washington (1400 GMT).
The blockade is intended by the United States to increase pressure on Iran to lift what U.S. officials describe as an effective closure of the Strait of Hormuz, the narrow shipping lane that handles roughly 20% of the world’s oil. The move follows a breakdown in weekend talks aimed at ending the ongoing war.
President Donald Trump has said the blockade is designed to force Iran to accept U.S. terms for ending a war that, according to U.S. statements in the present account, was launched by the U.S. and Israel on February 28. One of the conditions the administration has cited is reopening the Strait of Hormuz. Trump has also said reopening the strait was a condition of a ceasefire with Iran reached about a week earlier that is due to expire next week.
Experts and analysts have described the early enforcement of the blockade with caution. Noam Raydan of The Washington Institute for Near East Policy noted that maritime tracking showed at least one tanker executing a U-turn after the blockade began, but he warned that many vessels associated with Iranian oil shipments switch off tracking systems and go dark. "We just don’t know yet how effective it is. We are still in day two," Raydan said.
The logistics of the operation are substantial. The U.S. military says the blockade involves more than 10,000 U.S. personnel, over a dozen warships and dozens of aircraft. Military officials also said they will support freedom of navigation for vessels transiting the Strait of Hormuz, provided those vessels are not en route to or from Iran.
Markets reacted to the escalation. Oil prices jumped back above $100 a barrel before easing on Tuesday amid hopes that further talks might resume. U.S. officials have argued that if the blockade achieves its goals, it would remove Iran’s most significant negotiating leverage and allow the strait to reopen for international trade.
At the same time, analysts caution that a blockade constitutes an act of war, one that requires an open-ended commitment of substantial naval resources. They warn it could prompt renewed Iranian retaliation and place severe stress on an already fragile ceasefire arrangement.
Broader effects of the conflict already referenced in official and analyst accounts include a sharp increase in global oil prices - an approximate 50% rise tied to Iran-related threats to shipping - and heavy human and military tolls. The hostilities have been reported to have caused roughly 5,000 deaths. U.S. military operations have been described as having severely weakened Iran’s military capabilities, yet analysts say Iran has emerged with a more hard-line leadership and a concealed stockpile of highly enriched uranium.
Raydan warned that if the blockade endures, Iranian retaliation is likely. He pointed to Tehran’s past attacks on ships and noted Iranian threats to target Gulf states that host U.S. forces. "We’re in the testing period," he said, underscoring the uncertainty surrounding how both sides will act as the blockade continues.
Key points:
- U.S. destroyer intercepted two tankers leaving Chabahar port and ordered them to return; they were among six vessels Central Command said had turned back.
- The blockade, which began Monday at 10 a.m. Washington time (1400 GMT), includes more than 10,000 U.S. forces, over a dozen warships and dozens of aircraft, and is aimed at pressuring Iran to lift its effective closure of the Strait of Hormuz.
- Oil prices briefly rose above $100 a barrel following the announcement before easing on hopes of further diplomacy; disruptions to shipping potentially affect global oil markets and trade flows.
Risks and uncertainties:
- Potential for Iranian retaliation - Analysts warn a sustained blockade could provoke strikes against ships or Gulf states hosting U.S. forces, increasing regional military risk and threatening energy shipments.
- Open-ended resource commitment - Maintaining a long-term blockade requires a prolonged deployment of warships and forces, with strain on military logistics and possible escalation risks.
- Market volatility - Continued threats to shipping and changes in the security situation could keep global oil prices volatile, affecting energy, shipping and broader markets.