headline: US military expands Iran blockade worldwide, targeting ships carrying oil, metals, arms slug: 2026-04-16-us-military-expand…

  • The U.S. military expanded its blockade of Iran beyond Persian Gulf ports Thursday to allow forces worldwide to stop any ship tied to Teh…
  • The expansion extends U.S. naval enforcement authority to the Pacific and other regions, targeting vessels that departed before the block…
  • U.S. forces in other areas of responsibility “will actively pursue any Iranian-flagged vessel or any vessel attempting to provide materia…
  • The military also published a notice declaring that any “goods that are destined for an enemy and that may be susceptible to use in armed…

The U.S. military expanded its blockade of Iran beyond Persian Gulf ports Thursday to allow forces worldwide to stop any ship tied to Tehran or suspected of carrying supplies — from weapons and oil to metals and electronics — that could aid the Iranian government, Gen. Dan Caine, chairman of the Joint Chiefs of Staff, announced at the Pentagon.

The expansion extends U.S. naval enforcement authority to the Pacific and other regions, targeting vessels that departed before the blockade took effect earlier in the week outside the Strait of Hormuz. It comes as a ceasefire is set to expire in days, with mediators pressing for an extension to the truce that has paused nearly seven weeks of war among Israel, the United States, and Iran.

Broadened scope

U.S. forces in other areas of responsibility “will actively pursue any Iranian-flagged vessel or any vessel attempting to provide material support to Iran,” Caine told reporters.

The military also published a notice declaring that any “goods that are destined for an enemy and that may be susceptible to use in armed conflict” are “subject to capture at any place beyond neutral territory.” The notice authorizes boarding, searching, and seizing such goods from merchant vessels “regardless of location.”

The expanded contraband list distinguishes between categories. Weapons, ammunition, and military equipment are classified as “absolute contraband.” Oil, iron, steel, and aluminum are classified as “conditional contraband” on grounds that each can be used for civilian or military purposes. Electronics, power generation equipment, and heavy machinery may also be seized if “circumstances indicate intended military end-use,” the notice states.

Enforcement so far

More than 10,000 American troops are helping enforce the blockade on Iranian ports, according to defense leaders. In the first three days of the military action, 14 ships turned around rather than confront the naval blockade, according to U.S. Central Command, which oversees the Iran war. No ships had been boarded as of Thursday.

Caine described the protocol for vessels that approach the cordon, which is being enforced in Iran’s territorial seas and international waters — not within the Strait of Hormuz itself. “Any ship that would cross the blockade would result in our sailors executing pre-planned tactics designed to bring the force to that ship — if need be, board the ship and take her over,” he said.

U.S. Central Command has released a recording of a radio broadcast sent to vessels in the region stating the military was ready to use force if needed. “Vessels will be boarded for interdiction and seizure transiting to or from Iranian port,” the message said.

Some Iran-linked or sanctioned vessels that left through the strait appeared to halt their movements, turn off their radio transponders, or head back toward Iran’s coast, according to shipping data firms.

The Navy has 16 warships in the Middle East — 11 destroyers, three amphibious assault ships, one aircraft carrier, and one littoral combat ship — out of a battle force of roughly 300 total warships. Defense Secretary Pete Hegseth told reporters that “less than 10% of America’s naval power” is being used to enforce the blockade.

The operation also involves aircraft, surveillance, reconnaissance, and intelligence assets. Kevin Donegan, a retired vice admiral and former commander of the Navy’s Fifth Fleet based in Bahrain, said at a Middle East Institute webinar Thursday that coordinating the effort is logistically complex.

“It’s a pretty complex operation to make work,” Donegan said. “Not just from the intelligence standpoint, but positioning all the ships in the right way to make the intercepts if you have to.”

Blockade as one instrument

Donegan stressed that the naval cordon is not sufficient on its own to end the conflict. “For it to be most effective, this military tool is added to the other operational tasks that were being done and paired with — hopefully, diplomacy,” he said. “And if those two are scripted together in the right way, we can potentially get the outcomes we want.”

Adm. Brad Cooper, the head of U.S. Central Command, made a rare appearance in the Pentagon briefing room alongside Hegseth and Caine. Cooper said that before the ceasefire took effect, American service members and allied troops in the Persian Gulf had “fought together side by side.” He added that the U.S. had embedded specially trained air defenders alongside partner-nation soldiers “in creating the largest air defense umbrella in the world across the Middle East.”