The U.S. military has begun blocking the Gulf of Oman and the Arabian Sea, a move experts say could escalate into a more serious war during the two-week ceasefire.
The US Central Command says it has directed all ships to and from Iran since Monday morning, saying warships will monitor and intercept ships going to Iranian ports, regardless of country of origin.
That means ships traveling between non-Iranian ports can still pass through the Strait of Hormuz, but ships connected to Iranian trade may be stopped, searched or turned back.
This is not exactly what US President Donald Trump threatened on Sunday, when he said the US would close the entire Strait of Hormuz.
Trump told reporters on Monday that the blockade was designed to force Tehran to return to talks after peace talks broke down over the weekend.
CBC News spoke to analysts about how the blockade could play out.
Why do they do this?
The US intends to cut off oil exports to Iran, which generates about $200 million US a day.
Tehran has also levied a transit fee of up to $2 million US on some ships passing through the port, granting ships from friendly nations and blocking those from the US, Israel and its allies.
The fallout from the crisis has caused oil prices to soar in the US and elsewhere.
Mark Norman, a retired Royal Canadian Navy vice admiral and fellow at the Canadian Global Affairs Institute, says the blockade is “a terrible act.” He says it is strange that the US has successfully blocked the way it wanted to open since the conflict started.
“This is the only significant remaining pressure point, or point, that the United States has,” he said. “This is about money at the end of the day.”
David Carment, a professor of international affairs at Carleton University in Ottawa, says that the US and Israel do not fully understand that Iran has the ability to resolve and retaliate, and says that it is “not at all clear” that the US has a larger plan going forward.
President Donald Trump said on Monday that the US blockade of Iranian ports has begun, but he did not provide initial information about what, exactly, is happening around the Strait of Hormuz. Hear some of Trump’s words as he considers the status of negotiations with Tehran and what he expects next.
“Everything they’ve done up until now seems to lack a long-term strategy. It seems incredibly surprising,” Carment said.
“One minute they are negotiating, the next minute they are putting bigger and bigger obstacles on Iran. Meanwhile, Israel is doing very well if it wants to sideline Lebanon, targeting diplomats and leaders inside Iran, making it very difficult for the negotiation process to happen.”
Carment says that if he were to give the US the benefit of the doubt, he would say that this move has nothing to do with Iran as it is about forcing China, which is the world’s oil importer, to deal with this problem.
How will the US block the ships?
According to shipping tracking websites, two tankers linked to Iran – one carrying oil products and the other diesel – sailed ahead of the sanctions deadline on Monday morning.
US warships were spotted near the Persian Gulf earlier, as well as some further away.
Norman says the US military will have to establish patrols outside the port to stop ships trying to enter the strait – a process that will involve more surface ships, helicopters and long-range aircraft.
He says they will use the existing information that the ships have to broadcast digitally to know who is coming from where.
“Then the question becomes, how do you cut through these ships? And I think that’s a big challenge,” he said.
Norman says the U.S. military can do what it does with Venezuelan ships stranded in the Gulf of Mexico during the winter, when soldiers sometimes descend from helicopters to board and seize the ships.
CBC’s David Common explains what to expect in the Strait of Hormuz after the U.S. military said it would move to block shipping to and from Iranian ports.
“And that’s very good, especially if some of those ships are marked as Chinese,” he said.
Norman says that the blockade itself is an act of war, as is the seizure of another nation’s flagged ship.
“According to the international law of the sea, we are in a very bad situation here.”
Will it work?
Norman says he’s not sure a blockade is the best solution, but the Americans have “painted themselves into a bit of a corner” in a war with Iran.
The move comes amid a flurry of rhetoric, with Trump writing on Truth Social on Monday that any Iranian ships approaching the blockade would be “immediately destroyed.” The Iranian military and the Revolutionary Guard responded by threatening, “NO PORT in the region will be safe.”
Janice Stein, founding director of the University of Toronto’s Munk School of Global Affairs and Public Policy, told the CBC News Network that blocking Iran from exporting its oil is a serious pressure attack and may succeed in forcing another round of peace talks, although she said it is a “dangerous dance”.
“Its economy is already in bad shape. This will really increase the pressure on Iran,” Stein said.
Carmen says it’s “a bit of speculation on the part of the American people” if they think the blockade will be the final blow that will bring Iran to its knees.
With Iran blocking the Strait of Hormuz and the US threatening its blockade of major Iranian ports, China’s huge oil demand could be caught in the middle, says Janice Stein of the Munk School of Global Affairs & Public Policy. ‘This is a dance. Dangerous.’
He does not think this move will convince Iran to make a deal in the talks. On the contrary, he says, it could lead to a “re-escalation” of violence, with Iran following on its heels.
“Iran will now be forced, I think, to respond and target American assets if they are in neighboring regions,” Carmen said.
The US and Iran agreed last week to a two-week ceasefire that will expire on April 22 if peace talks fail.
