By Phil Stewart
WASHINGTON, April 12 (Reuters) – The U.S. naval blockade of Iran is a major, open-ended military effort that could spark new retaliation from Tehran and put greater strain on an already fragile ceasefire, experts say.
President Donald Trump said in a social media post that the US Navy would “begin the process of interdiction of any and all vessels attempting to enter or leave the Strait of Hormuz” after peace talks in Islamabad failed to reach an agreement this weekend.
The U.S. military’s Central Command later said the embargo would only apply to ships bound for or bound for Iran, including all Iranian ports in the Arabian Gulf and the Gulf of Oman. It will take effect at 10 a.m. Monday in Washington (1400 GMT), CENTCOM said.
Trump also said the U.S. military would sanction ships paying tolls to Iran, if those ships are now in international waters. In Truth Social, Trump wrote, ‘No one who pays illegal tolls will be able to travel safely on the high seas.
The ultimate goal, Trump said, is to force Iran to effectively close the strait, a choke point for 20% of the world’s oil, to all but countries that secure safe passage from Tehran.
If Trump’s strategy succeeds, he will eliminate Iran’s biggest leverage point in negotiations with the United States and open the strait again for world trade, potentially driving down oil prices. But a blockade, experts say, is an act of war that requires an open-ended commitment of a large number of warships.
“Trump wants a quick fix. The reality is, this mission is difficult to execute alone and potentially unstable in the medium to long term,” said Dana Stroll, a former senior Pentagon official during the Biden administration who is now at The Washington Institute for Near East Policy.
Iranian retaliation
The U.S. military has not provided basic details about the blockade, including how many U.S. warships will enforce it, whether warplanes will be used and whether any Gulf allies will assist in the effort. Central Command declined to respond to a request for comment.
With enough warships, the U.S. Navy could establish a blockade that would deter many commercial tankers from trying to power through Iranian oil, experts say.
But will the United States be prepared to board and capture or damage or sink ships trying to break the blockade? What if they carry oil for China, a major power, or US partners like India or South Korea?
And what will Iran do? Retired Admiral Gary Roughead, the former chief of US naval operations, has warned that Iran could fire on ships in the Gulf or attack the infrastructure of Gulf states that host US forces.
“I honestly believe that if we start doing this, there will be some kind of response from Iran,” Roughead said.
Since the US and Israel started war on February 28, the threat of Iranian shipments has sent world oil prices up nearly 50%.
Trump said on Sunday that oil and gasoline prices could remain high https://www.reuters.com/world/asia-pacific/trump-says-us-start-blockading-strait-hormuz-2026-04-12/ through November’s US midterm elections in the United States, where Trump’s public could see Republicans lose control of Congress. War is already unpopular.
The gas price problem
Frustrated by Iran’s refusal to end the war on his terms, Trump also on Sunday raised the possibility of resuming US strikes inside Iran, citing the missile factory as a possibility.
US Senator Mark Warner of Virginia, the ranking Democrat on the Senate Intelligence Committee, questioned the strategy, saying Iran could send speedboats to mine the strait or plant bombs against tankers.
“How is this going to lower gas prices?” Warner asked on CBS’ “Face the Nation.”
Thousands of US military strikes have severely weakened Iran’s military. But analysts say Tehran has emerged from the conflict as a thornier problem for Washington, with more hardline leadership and buried stockpiles of highly enriched uranium.
Trump threatened on Sunday that “any Iranian who fires at us or peaceful ships will be thrown into hell!”
Iran’s Revolutionary Guards have warned that military vessels approaching the strait would be considered a violation of the ceasefire and dealt with harshly and decisively, underscoring the risk of a dangerous escalation.
Stroll said a long-term, international effort is needed to solve the crisis.
“In the long term, this needs to be resolved through diplomacy and international political will,” she said.
(Reporting by Phil Stewart; Editing by Sergio Nunn and Deepa Babington)
