The US military is preparing to board Iran-linked vessels and oil tankers in the coming days, a move that will expand a conflict largely confined to the Strait of Hormuz into a global crackdown.

General Dan Caine, the chairman of the Joint Chiefs of Staff, announced the escalation on Thursday, according to US officials who spoke with The Wall Street Journal.

Caine said the US 'will actively pursue any Iranian-flagged vessel or any vessel attempting to provide material support to Iran'.

'This includes dark fleet vessels carrying Iranian oil. As most of you know, dark fleet vessels are those illicit or illegal ships evading international regulations, sanctions or insurance requirements,' Caine added.

This mission, dubbed Economic Fury, will be executed with the help of US Indo-Pacific Command and enforced in addition to the US Navy's blockade of all Iranian ports on the Arabian Gulf and the Gulf of Oman.

The US has already turned away 23 ships that have tried to leave Iranian ports, according to US Central Command.

This comes as the Iranian military has reasserted 'strict control' over the Strait of Hormuz, attacking several ships that have tried to pass through the narrow waterway on Saturday.

The strikes from Iran - which allegedly involved two Indian ships - came just a day after Iran's foreign minister said the Strait of Hormuz was open to commercial traffic. 

President Donald Trump took the declaration from the foreign minister as genuine, announcing on Friday morning that the strait was 'COMPLETELY OPEN AND READY FOR BUSINESS'.

Trump followed that up with a series of optimistic statements about negotiating an end to the war. He even said that Iran agreed to hand over its remaining supply of highly enriched uranium to the US, something Iran has denied. 

Iran’s parliamentary speaker, Mohammad Bagher Ghalibaf, warned later on Friday that if the US blockade continued, 'the Strait of Hormuz will not remain open'.

The blockade has continued and the Trump administration has not shown any signs of budging on any of Iran's demands.

Trump is optimistic that the blockade, as well as intercepting Iran-flagged ships around the world, will eventually force the Iranians to the table by severely limiting imports into the country.

Previously, Iran's stranglehold over the Strait of Hormuz was a tactical advantage, allowing them to skyrocket global oil and gas prices. Roughly 20 percent of the world's daily oil supply passes through the strait, making it a vital chokepoint.

The president's strategy to cut off Iran from the world market is quite similar to what he has done with Cuba by heavily restricting the oil flowing into the country.

Like in Iran, he is seeking regime change in the island nation, which has been under communist rule since Fidel Castro came to power in 1959. 

The push to increase economic pressure comes as a temporary ceasefire between Iran and the US is set to expire next week.

Peace talks held last weekend in Pakistan failed to produce a breakthrough or any permanent halt in hostilities between the two sides. Another round of negotiations has not been scheduled.

Both sides have been taking precautions in case fighting resumes, with Iran retaining thousands of medium- and short-range missiles. The country is also retrieving launchers from underground storage areas, many of them buried within mountainous regions.

Defense Secretary Pete Hegseth has said US forces are 'maximally postured' to pick up where they left off if diplomacy fails. 

Hegseth has also said striking Iran's power plants are still an option, even though experts say that would be against international law. The move could also invite Iran to retaliate by bombing energy infrastructure in Saudi Arabia and other Gulf Arab countries allied with the US.

Trump administration officials are reportedly loath to use ground troops, something that would lead to US service members dying and a potential backlash from the American public.

Trump and his allies have largely settled on the economic pressure campaign as the way forward.

As part of Economic Fury, the Treasury Department announced Wednesday that it had sanctioned even more companies and individuals with ties to 'Iran’s illicit oil transportation infrastructure'.

The newly-sanctioned ships and firms are controlled by oil shipping magnate Mohammad Hossein Shamkhani, according to Treasury Secretary Scott Bessent.

Mohammad Hossein Shamkhani is the son of Ali Shamkhani, a top security adviser to Ayatollah Ali Khamenei. Ali Shamkhani was killed along with the Iranian leader in the Israeli airstrike in late February that started the war.

There are hundreds of sanctioned Iranian-linked vessels that could now be boarded or intercepted by the US military. 

It could mirror how the US Navy interdicted at least seven oil vessels with ties to Venezuela both before and after Nicolas Maduro was captured in a late-night operation in early January.

Acting Attorney General Todd Blanche has also said he will prosecute anyone who buys or sells sanctioned Iranian oil. 

The Daily Mail has reached out to the White House for comment.