Iran has vowed to retaliate against expanded US economic sanctions that the Americans said would cut off Iran's economic ​lifelines, with Tehran expressing confidence that major trading partners would resist Washington's pressure campaign.

US Treasury Secretary Scott Bessent on Monday unveiled measures aimed at further isolating Iran, but stopped short of the ‌most punishing sanctions, saying countries that continued trading with Iran risked being forced out of the dollar-based financial system.

The widening US sanctions

The US Treasury Department said in a press release that the new sectoral sanctions determinations target five critical sectors – digital assets, technology, gold, aviation and shipping – that the US says Iran has relied on to prop up its economy.

Read more: US threatens 'economic D-Day' sanctions on Iran

The measures marked the beginning of "a sustained and systematic campaign to close every financial resource" that supports Iran, the department said. It added that "any entity that facilitates money laundering or sanctions evasion on behalf of Iran risks being cut off from the US financial system."

The department is expanding the categories of "Iran-related conduct" that the US might sanction in the future, and said "every country will be given a defined timeline to shut down the Iran-related activity" the US has identified.

Meanwhile, the department sanctioned nearly 60 entities, individuals and vessels in multiple jurisdictions that is said enable Iran's activities, including illicit nuclear and missile technology procurement and oil-revenue generation networks. It also suspended several general licenses that previously authorized certain remittance payments to Iran and Iranian access to the US cultural and academic system, and released additional guidance on the sanctions risks associated with complying with Iranian demands regarding shipping in the Strait of Hormuz.

Bessent also disclosed that US President Donald Trump has been calling world leaders with specific requests to cease their interactions with Iran.

Iran strikes a defiant tone

Iranian Economy Minister Ali Madanizadeh said Iran is fully prepared for the US sanctions, which cannot cut off Iran's financial lifelines.

"Naturally, the enemies intend to launch an economic terrorist attack on us, but we also have our own tools and know how to play the game. Our defense is no longer so defensive; the enemies should wait for an attack," ​Madanizadeh told state television.

In a post on X, Iranian Parliament Speaker Mohammad Bagher Ghalibaf said: "Iran's trading partners, both in the media and through messages sent to us, have made it clear that they don't take these statements into account anywhere."

Brigadier General Hossein Mohebbi, a spokesperson for Iran's Islamic Revolutionary Guard Corps, vowed ​heavy blows to US vital interests and energy chokepoints if Iran's infrastructure is threatened, Press TV reported.

Iranian President Masoud Pezeshkian said on Monday that the ​US must correct its tone and approach in interacting with Iran, because relying on coercion and bullying will only complicate the processes, during a meeting with Pakistan's Chief of Army Staff Field Marshal Syed Asim Munir in Tehran.

Earlier, Mohsen Rezaei, secretary of Iran's Supreme National Security Council, said that Iran will regard any country's participation in or support for America's economic war against the Iranian people as an act of war.

What the sanctions will lead to

The latest economic escalation comes as nearly six months have passed since the US and Iran launched strikes against each other in late February, raising further questions about how the confrontation will evolve.

In an interview with CMG, Li Zixin, a Middle East expert at the China Institute of International Studies, said Iran could respond to the escalating US pressure by leveraging its control over the Strait of Hormuz, its geopolitical influence, and its decades of experience in countering sanctions.

Li said Iran has built up military deterrence in the strait while also moving toward institutionalized control of the strategic waterway.

"Thousands of sea mines and anti-ship missiles cover the entire strait, giving Iran substantial military leverage over this vital waterway," Li explained, adding that "the newly established Persian Gulf Strait Management Authority has adopted a 'one vessel, one inspection' system, transforming what were previously temporary measures into a routine and institutionalized mechanism of control."

Only one ​commodity vessel transited ‌the Strait ⁠of Hormuz on Monday, ‌the lowest ‌number since May ‌7, according to shiptracker Kpler.

Iran's geopolitical leverage could also play a role, Li said. Tehran has threatened to regard countries participating in US sanctions against Iran as enemies, potentially raising the security costs for neighboring countries that cooperate with the US.

Meanwhile, Jamal Abdi, president of the National Iranian American Council, told CGTN that the latest US economic measures represent "not a new approach" or "a shift in strategy," but rather "a retreat back to a strategy" that Washington has pursued for years. He warned that the move is unlikely to bring stability, as Iran will not simply sit by and do nothing in response.

Besides, US media reports showed that comparing with Iran, which has been used to decades of sanctions, the economic sanctions could hit Americans hard if Iran retaliation accelerates.

Neel Kashkari, president of the Federal Reserve Bank of Minneapolis, told CBS's Face the Nation that "what's happening in the Middle East, the conflict with Iran, is now a big driver of what's happening on inflation because, as you know, energy goes into every facet of the US economy, and the longer that conflict, the more turmoil there is. The longer it goes on, the bigger effect it ends up having on the US economy and on inflation."

US consumers have been feeling the impacts of the rising gas price. The average price for a gallon of gas (3.78 litres) is $4.09, up from $2.98 before the war, according to the American Automobile Association, which tracks daily petrol prices.

"If sanctions provoke Iranian retaliation against Gulf shipping, materially reduce oil exports, or cause insurers and shipping companies to avoid the region, then Americans could feel it very quickly through gasoline, diesel, airfares, freight costs and ultimately inflation," John Deal, managing director of capital markets at Post Oak Group investment bank, told Al Jazeera.

(With input from agencies)