The first week of the US military campaign against Iran has cost around $6 billion, including about $4 billion spent on munitions and advanced missile interceptors, as Pentagon officials told Congress additional funding will likely be needed to sustain operations and replenish stockpiles.

The figures were disclosed during congressional discussions this week.

According to a report in The New York Times, about 4,000 Iranian targets have been struck, including missile launchers, naval vessels and air defence systems, significantly weakening Tehran’s ability to retaliate.

Gen Brad Cooper, head of US Central Command, said Iran’s ballistic missile launches have dropped by about 90% since the start of the conflict, while drone attacks have declined by roughly 83%.

Despite the losses, Iran still retains significant military capability, including an estimated half of its missile arsenal, he added.

Lawmakers in Washington are preparing for a possible supplemental funding request from the administration in the coming weeks as the rapid spending comes under scrutiny from both Democrats and Republicans.

Critics have warned that expensive interceptor missiles — some costing millions of dollars each — are being used at a pace that could strain the US defence industrial base and create shortages in other strategic theatres.

The conflict began on February 28 when the United States and Israel launched large-scale strikes on Iran, reportedly martyring more than 1,200 people, including Iran’s Supreme Leader Ali Khamenei and several senior military officials.

Iran has retaliated with missile and drone attacks targeting Gulf countries, US bases, diplomatic facilities and military personnel across the region, as well as multiple Israeli cities.

The escalation has also raised concerns about global energy supplies as maritime traffic through the Strait of Hormuz, a key route carrying about 20 million barrels of oil per day, has declined sharply.