US threatens ‘indefinite’ blockade against Iran: How long can it last? 

The United States has threatened to maintain an “indefinite” naval blockade on Iranian ports and impose new measures to isolate Iran economically as ceasefire talks between the two countries remain in deadlock.

However, lawmakers in the US raised the alarm this week following reports of dire conditions on board the flagship USS Abraham Lincoln, including accounts of sailors trying to jump overboard.

Furthermore, despite President Donald Trump’s claims that the US has “full control” of the Strait of Hormuz, the vital waterway that Iran closed in early March shortly after the start of the war, only a handful of ships have been able to pass through this week.

“Claims and repeated posts by US officials that the Strait of Hormuz is no longer blocked do not change the reality,” Iran’s Persian Gulf Strait Authority (PGSA) posted on X on Wednesday.

“The Strait of Hormuz remains blocked and will not be reopened until Iran’s conditions are accepted,” it added.

So how long can the US really keep a naval blockade going, and can Iran just wait it out?

Here’s what we know:

What has the US said?

On Thursday, US Defense Secretary Pete Hegseth told reporters that the US military can maintain a naval presence in the region “indefinitely” to enforce its blockade of Iranian ports.

“Indefinitely, the United States Navy can maintain a blockade like that because we’ll rotate ships in and out, as we have, and we’ll continue to,” Hegseth told reporters during a trip to Panama.

US Treasury Secretary Scott Bessent also said the US will apply new economic measures to pressure Iran.

“Watch this space for more announcements coming next week because we are going to apply measures that have never been seen in the history of economic isolation on a country,” Bessent said in an interview on Newsmax on Thursday.

“It will be a combination of economic isolation the world has never seen before, and the continued blockade in the Strait of Hormuz that will keep anything from going in or out of the Iranian ports,” he added.

Questions have been raised about the conditions on board the USS Abraham Lincoln, the US’s flagship aircraft carrier that is conducting maritime security and blockade operations around the Strait of Hormuz.

Reports by two US publications that cover military affairs, the Navy Times and Stars and Stripes, cited family members of military personnel on board the vessel who said they were suffering from declining mental health and morale, and cases of suicidal ideation.

The Navy Times spoke on the record with one sailor’s wife, identified as Annabelle Loma, who said he had attempted to jump overboard amid what she described as “severe burnout”.

The reports have prompted urgent questions from US lawmakers.

In a letter to Secretary of Defense Pete Hegseth, Democratic Senator Richard Blumenthal wrote that the aircraft carrier, which departed San Diego, California, in November last year with more than 5,000 US sailors and Marines on board, has now been “continuously at sea for a record length of nearly seven months”. That surpasses any previous deployment of a US aircraft carrier without a port stop.

Blumenthal raised the alarm over reports of deteriorating mental health on board, as well as shortages of basic supplies, water contamination, an increase in safety incidents, and even disruptions to mail services, through which those on board receive care packages.

“These reports warrant immediate attention, but they also raise a broader question: whether the Navy can sustain the operational tempo now being demanded of its carrier force, particularly as this administration repeatedly commits US forces to conflicts of its own choosing and increasingly relies on aircraft carriers to sustain those operations,” Blumenthal wrote.

US senators are demanding answers from Hegseth. US Senate Minority Leader Chuck Schumer called for Hegseth to be removed from his position over his handling of the aircraft carrier.

In a post on X, Schumer wrote, “When Pete Hegseth was nominated, everyone knew he was completely incompetent. Now our brave sailors are paying the price in a horrific and unfathomable way.”

“Pete Hegseth must be fired immediately,” he added.

California lawmakers led by Representative Mike Levin also demanded answers from Hegseth and Acting Secretary of the Navy Hung Cao about the situation on board the aircraft carrier.

In a post on X, Democratic Congressman Levin shared a letter signed by four US lawmakers, stating that “the plans in the works to relieve the USS Lincoln are not enough.

“We need clear and honest information from the Department of Defense about the operational failures that led to the problems aboard the USS Lincoln to ensure this never happens again,” the letter added.

“Why weren’t unsanitary conditions immediately addressed? Why didn’t service members receive adequate mental health support? Why did the Navy not communicate these problems early and often to families and the appropriate government officials?” it asked.

Hegseth rejected reports of worsening conditions on board the USS Abraham Lincoln, calling the reports “completely misrepresented”.

Further questions have arisen after several media outlets, particularly Iranian media, reported that seven US Navy personnel had been killed and several wounded in a fight on the USS Abraham Lincoln.

The US has strongly denied this. US Central Command (CENTCOM) posted on X on Friday that this claim, as well as that of sailors expressing suicidal ideation, were false.

“The Sailors and Marines of the Abraham Lincoln Carrier Strike Group remain resilient and resolved after more than 260 days at sea,” it added.

“No service members aboard the aircraft carrier have died, and the one sailor who fell overboard on August 3 was quickly and safely recovered.”

The Trump administration claims it will rotate ships in and out to relieve the pressure on its naval forces in the Gulf, with reports on Friday that the aircraft carrier USS George Washington, currently in the Pacific, has begun heading towards the Middle East.

But experts say ships positioned in the Gulf have already been there for too long without a break.

Harlan Ullman, a retired senior naval officer and chairman of the strategic advisory firm The Killowen Group, said USS Abraham Lincoln needs routine maintenance in port, considering how complex and advanced a vessel it is.

Ullman told Al Jazeera that ships require onshore care to keep advanced technology operational over long periods.

“Ships need maintenance, particularly ships that are extremely complicated with very advanced weapon systems such as nuclear-powered carriers with very advanced systems, and there are things that you cannot do in terms of maintenance under way,” Ullman said.

“There are lots of things that you can do at sea, but there are far more things that can only be done in port,” he pointed out.

He noted that extended deployments, such as the nine months for USS Abraham Lincoln, “erode the readiness and capability of that ship the longer it’s at sea, and it lacks the ability to repair and extend maintenance”.

He added that the Trump administration must prioritise naval readiness over politics, saying “this is a national issue, not a local one; and the administration should not be so defensive. It should say, ‘OK, we’ll see what’s going on, and then if there are some issues, we’ll take care of them.’”

Can Iran withstand the US blockade on its ports?

The US is hoping it can cripple Iran’s economy by keeping its naval blockade in place.

Trump has already signalled he would rather rely on squeezing Tehran’s economy than return to a military offensive amid reports that the US may be running low on defensive munitions, something the US president has denied.

“We are low-keying it,” Trump told the news website Axios in an interview on August 9 regarding the US approach to the war on Iran.

The following day, Trump claimed that Iran is in “very bad shape” financially, citing high inflation and difficulty paying its soldiers, and credited a US naval blockade in place.

The US blockade has squeezed Tehran’s most important source of income: Crude oil. Iran has reportedly already lost at least $6bn in oil revenues since the blockade, which Tehran called “an act of piracy“, began on April 13.

However, experts say there are several reasons that Iran is in a stronger position than the US claims.

Ali Vaez, deputy programme director for the Middle East and North Africa at the International Crisis Group, said: “Iran could raise the stakes by targeting US naval assets or pushing the Houthis [in Yemen] to tighten the noose around regional energy exports.

“Tehran’s calculus is that, in every game of chicken with Washington, the US has swerved first – and it sees little reason to believe this time will be different,” he added.

Since the US-Israel war on Iran began, Trump has on several occasions threatened military action against Tehran before backing down at the last moment, observers note.

Furthermore, Iran’s control of the Strait of Hormuz is a major piece of leverage, experts say. Iran has repeatedly stated it will not reopen the critical waterway until the US naval blockade is lifted, sanctions are lifted and its assets are unfrozen.

On Thursday, the commander of Iran’s Islamic Revolutionary Guard Corps Navy, Rear Admiral Ali Azmaei, said: “We have complete and decisive control over all movements. No movement in this strait goes unnoticed by the warriors of the IRGC Navy,” in a statement carried by Tasnim news agency.

Iran sees itself as waging an economic rather than a military war on the US, said Mostafa Khoshcheshm, a professor at the University of Applied Sciences and Technology in Tehran.

“Iran knows that if it’s going to defeat the United States, it should be asymmetrical warfare, and in this economic warfare, the Strait of Hormuz matters the most,” Khoshcheshm told Al Jazeera.

Iran is also hoping that the US will simply “acknowledge defeat and leave the region”, said the professor.

Another angle is the economic pressure Iran has been able to apply to neighbouring countries by launching attacks on US military assets hosted there as well as on infrastructure and energy facilities.

Mehran Kamrava, professor of government at Georgetown University in Qatar, told Al Jazeera this week: “What we have seen is that the Iranians are trying to put economic pressure on the regional neighbours, particularly on countries like Qatar, UAE, Saudi Arabia and Kuwait, so that they would in turn put pressure on the US to negotiate with Iran.”

Kamrava added that he was sceptical that US economic pressure on Iran would prove effective, particularly as Iran’s leaders are not under the same internal political pressure as the Trump administration.

“Tehran is under tremendous economic pressure, but we need to bear in mind that Iran’s political system is ultimately a very repressive one. It’s not that people making decisions directly care about the plight of the middle classes,” he said.

“They want to stay in power,” he added. “So I’m not sure if this tactic is going to work at this point.”