Karachi, Pakistan — At Karachi port, the largest in Pakistan, 3,000 stranded containers hold cargo that was meant to be shipped to Iran. What’s in them is not known.

But the vessels that were supposed to collect them have not arrived — and with tensions in the Strait of Hormuz escalating, there is no clarity on when those ships might finally be able to reach Karachi.

This disruption is part of a wider pressure strategy shaped under President Donald Trump – one that analysts say is designed not to halt trade completely, but to control it.

“Iran is collapsing financially,” Trump wrote on Thursday on Truth Social. “They want the Strait of Hormuz opened immediately- Starving for cash!”

For the first six weeks of the US-Israel war on Iran that began on February 28, Tehran imposed an access system to control which ships transited the strait while also earning toll payments.

But since April 13, the Trump administration has imposed its naval blockade that has effectively stopped ships sailing through the strait that either left or were destined for Iranian ports.

The US naval blockade didn’t just hurt Iranian exports – the Trump administration effectively controls Iran’s ability to import goods it desperately needs. Analysts say, in some ways, that economic chokehold could exert even more pressure on Iran than the American military might.

“[Iran’s] storage reservoirs would fill quickly, some estimates suggest within a few weeks, forcing production shut-ins,” finance and policy analyst Javed Hassan, an adviser to the Islamabad-based Centre for Research and Security Studies (CRSS), told Al Jazeera.

“Export revenues, the state’s fiscal lifeline, would contract sharply. And while Iran has improved domestic agricultural capacity, its food security still depends in part on imports and foreign exchange, another channel of pressure.”

But, Hassan cautioned, Iran has also built “resilient architecture” during decades of surviving US-led sanctions. It already has millions of barrels of oil — some estimates suggest up to 170 million barrels — that are on tankers already out at sea, well beyond the Gulf of Oman. That could “sustain export revenues for a couple of months”.

Equally important, Hassan said, are overland and inland sea corridors that Iran can use – and already is using,  according to some reports. Some run through Central Asia and the Caucasus.

Iranian officials have also asked Pakistani counterparts for help in designing an alternative route for their goods.

A land route?

Documents shared between Pakistani industry leaders and government officials, and seen by Al Jazeera, show that Iranian and Pakistani business and industry leaders are discussing the possibility of a land route to send the stranded containers across the 900km border between the neighbours.

Pakistani officials confirmed the consultations, speaking on condition of anonymity because of the sensitivity of the subject and because the idea, for now, is just that: a possible answer to ease Karachi’s burden of hosting thousands of Iran-bound containers.

Al Jazeera has contacted the Iranian government for comment, but did not receive a response when this article was written.

If the plan materialises, Pakistani trucks will carry the cargo to the border, then Iranian transport would take over.

The documents seen by Al Jazeera, suggest that Iran would even be willing to pay Pakistani truckers extra if they were willing to go all the way to the eventual destination inside the Islamic Republic, despite the land route being slower and more expensive than shipping.

A strait that’s neither open nor closed

The status of the Strait of Hormuz is unclear. Officially, it is not closed. Since imposing restrictions on transit in early March, Iran has allowed passage to ships from countries seen as aligned with it — including Pakistan, Malaysia and Iraq — without paying transit fees, often after quiet diplomatic engagement.

Others, including vessels from India, have also been allowed through, but under conditions such as detailed documentation and prior clearance.

But in at least some cases, payments have been made, according to Lloyd’s List. The shipping journal says by late March, at least some of the ships paid in Chinese Yuan, settling their deal with Iran outside the US dollar system. Some reports have suggested that Iran has charged up to $2m for each vessel. Some payments have been made in cryptocurrencies. Iran already has barter agreements with multiple countries, including Russia, China, and Pakistan, bypassing sanctions and the dollar tracking system.

Hamidreza Haji-Babaei, second deputy speaker of Iran’s parliament, said on Thursday that the first revenue from tolls collected on vessels passing through the Strait of Hormuz had been deposited into the Central Bank of Iran, the semi-official Tasnim news agency reported. Iranian state media and government officials have not confirmed the amount deposited, but it was the first official confirmation from Iran of shipping toll collection.

But there are other ships that remain stuck. Vessels linked to the United States, Israel, or countries enforcing sanctions are denied outright by Iran’s Hormuz-control regime.

Then there’s a cost, say analysts and experts, that goes beyond the toll.

Cost of risk

According to Mohammed Rajpar, chairman of Pakistan Ship’s Agents Association, the cost of insurance has soared since the start of the war.

“Before the conflict, war-risk insurance stood at around 0.12 percent of a vessel’s value. It has since climbed to roughly 5 percent – if coverage is available at all,” he told Al Jazeera.

“For a very large crude carrier valued at $100 million, that means a premium of about $5 million for a single transit.”

That “calculation still works”, he explained, for oil carriers. A very large crude carrier (VLCC) can carry up to two million barrels of crude – worth around $200m.

“Even with higher premiums and transit costs, the margins can absorb it,” he said.

But for container shipping, the picture is less clear. Cargo values can be high. But margins are tighter. Ownership is fragmented. And timelines are fixed – goods expire.

So while crude flows selectively for those who can pay the combined cost – if their ship has the correct flag – everything else waits or gets rerouted.

Iran’s calculation

Jamil Ahmed Khan, a former Pakistani ambassador, said the constraints imposed by the US naval blockade would hurt Iran.

“Iran remains significantly dependent on oil revenue, which cannot be fully realised when key export routes — particularly maritime ports — are restricted or disrupted,” he told Al Jazeera. “Such constraints directly impact the country’s foreign exchange earnings and overall economic stability”.

Iran also relies on imports of refined fuel and food grains. “This reliance makes the country vulnerable to supply chain disruptions and external pressures,” he said. “These economic and structural dependencies could contribute to rising public frustration, particularly if shortages or inflation intensify”.

Yet Hassan of the  CRSS warned against looking at the impact of the naval blockade on Iran only through the lens of a “standard cost-benefit world”.

“When a leadership perceives an existential threat, economic rationality as we define it in peacetime loses primacy. Endurance becomes the objective function. Iranian decision-making reflects this logic,” he said.

“They could plausibly keep the strait disrupted for longer than many assume, precisely because the calculus is not marginal but existential. There is a long tradition in such conflicts captured in a stark formulation often attributed to Ho Chi Minh: you may inflict greater losses, but the side that endures longer prevails. That mindset matters”.