The United States announced Monday that it has begun enforcing a sweeping naval blockade along Iran’s entire coastline, expanding beyond the Strait of Hormuz. The move follows President Donald Trump’s earlier vow to shut down the critical shipping lane, after Iran effectively halted most maritime traffic there in response to joint U.S.-Israeli strikes. The blockade comes after negotiations failed to end the war that began February 28, despite a temporary two-week truce.

U.S. Central Command (CENTCOM) said the operation began at 10:00 a.m. ET and places all Iran-linked maritime traffic under its control.

“The blockade will be enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas, including all Iranian ports on the Arabian Gulf and Gulf of Oman,” CENTCOM said. “CENTCOM forces will not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports.”

According to Reuters, U.S. forces issued a warning to mariners outlining enforcement measures.

“Any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture,” the message said. “The blockade will not impede neutral transit passage through the Strait of Hormuz to or from non-Iranian destinations.”

Officials have not yet detailed how the blockade will be carried out, though reports indicate more than 15 U.S. warships are already involved.

At the same time, the U.K. Maritime Trade Operations center issued guidance noting that the restrictions cover Iran’s entire coastline, including ports and energy infrastructure. While passage through the Strait of Hormuz for non-Iranian destinations is technically allowed, vessels may encounter military oversight, communications checks, or inspections. Neutral ships currently docked in Iran have been given limited time to leave.

On Sunday, Trump announced the move on Truth Social, declaring that the U.S. Navy would begin “BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz.”

“I have also instructed our Navy to seek and interdict every vessel in International Waters that has paid a toll to Iran. No one who pays an illegal toll will have safe passage on the high seas,” Trump said.

“Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!” he continued.

Maritime intelligence firm Lloyd’s List confirmed that shipping traffic through the strait effectively stopped following Trump’s announcement, with at least two vessels turning back mid-transit.

Although a ceasefire allowed limited ship movement in recent days, traffic has remained minimal and exposed to risk.

Trump also addressed concerns about Iranian sea mines, telling Fox News, “it won’t take long to clean out the strait” and that “numerous countries are going to be helping us,” including the United Kingdom, though foreign involvement has not been confirmed.

Previously, Iranian authorities issued routing instructions to vessels, warning that straying from designated paths could result in striking mines. A Lloyd’s List spokesperson told the BBC: “We know Iran is essentially still in control of the strait, and the assumption is that ship owners will still need to seek permission from the IRGC… and how that’s going to work is still not clear.”

Despite Trump’s claim of international cooperation, NATO allies said Monday they will not participate in the blockade, indicating they may only reconsider after the conflict ends.

Israel, however, expressed full support. Prime Minister Benjamin Netanyahu said Monday that Israel is coordinating closely with Washington.

“Iran violated the rules [of the peace talks in Pakistan], President Trump decided to impose a naval blockade,” Netanyahu said.

Iran responded sharply, with the Islamic Revolutionary Guard Corps warning that foreign military presence in the Strait of Hormuz violates the ceasefire. An Iranian military spokesperson called the blockade illegal and “amounts to piracy.”

Iran also warned of broader consequences.

“Security in the Persian Gulf and the Sea of Oman is either for everyone or for NO ONE,” the military said. “NO PORT in the region will be safe.”

Separately, a commercial vessel reported witnessing an explosion and fire at the Fateh Oil Field off the UAE coast, though no casualties or damage to shipping infrastructure were confirmed.

Iranian Parliament Speaker Mohammad Bagher Ghalibaf mocked the blockade’s economic impact, posting: “Enjoy the current pump figures. With the so-called ‘blockade’, soon you’ll be nostalgic for $4–$5 gas.”

He also warned: “If you fight, we will fight … We will not bow to any threats.”

Trump, meanwhile, claimed U.S. forces have already “obliterated” 158 Iranian vessels.

“Iran’s navy is laying [sic] at the bottom of the sea,” he said.

However, analysts note that while Iran’s conventional navy has taken heavy losses, the IRGC’s fleet of smaller, fast-attack boats remains largely intact. Experts estimate more than 60 percent of these vessels are still operational.

Trump dismissed their threat, saying they are not “much of a threat,” and suggested they could be neutralized using tactics similar to anti-drug trafficking operations.

Since the war began, Iran has leveraged the narrow Strait of Hormuz to restrict access and drive up global oil prices, even demanding payments from some ships for safe passage.

The blockade could cut off a major revenue stream for Tehran but also risks pushing energy prices higher worldwide, raising concerns among U.S. officials and business leaders about economic fallout.

Some analysts question how effective the blockade will be. Shipping expert Lars Jensen said it may only stop “a very tiny trickle of vessels” in the near term, noting that ships paying Iran were already under sanctions.

Trump signaled indifference to renewed negotiations.

“I don’t care if they come back or not,” he said. “If they don’t come back, I’m fine.”

China’s role is becoming increasingly significant, as it relies heavily on Iranian oil. Chinese Defense Minister Adm. Dong Jun said Beijing is monitoring the situation.

“We have trade and energy agreements with Iran. We will respect and honor them and expect others to not meddle in our affairs. Iran controls the Strait of Hormuz, and it is open for us,” he said.

CENTCOM declined to clarify how it would handle Chinese vessels attempting to transit the strait.

Reports indicate the U.S. is also considering renewed limited strikes inside Iran, though a broader campaign is viewed as unlikely due to escalation risks.

Separately, talks in Pakistan revealed major disagreements over Iran’s nuclear program. The U.S. reportedly demanded a 20-year halt to uranium enrichment, while Iran proposed a much shorter timeline.

Trump said Iran is seeking a deal but insisted any agreement must prevent it from obtaining nuclear weapons.

“They’d like to work a deal,” he said.

Meanwhile, the USS George H.W. Bush is heading toward the eastern Mediterranean to replace the USS Gerald R. Ford, which is undergoing repairs.

British Prime Minister Keir Starmer reaffirmed Monday that the U.K. will not join the blockade, emphasizing the need to reopen the strait.

“All the time the strait is shut or not free for navigation in the way it should be, that means oil and gas is not getting to market, that means the price is going up, and everybody listening to this is facing higher energy bills,” Starmer said. “I don’t want that to happen. I want their energy bills to be stabilized and lower.”

On the diplomatic front, Russia signaled willingness to accept Iran’s enriched uranium as part of a future deal, while mediators from Pakistan, Egypt, and Turkey continue efforts to revive negotiations.

At the same time, Israel confirmed it has launched targeted ground operations in southern Lebanon, with Netanyahu stating there is “no ceasefire in Lebanon” and vowing continued strikes against Hezbollah.

Analysts suggest the blockade is primarily economic pressure rather than a step toward broader war.

“The blockade is a pressure tactic, to be sure, but not primarily a military one,” wrote David Ignatius. “Trump has no appetite for further armed conflict… His aim instead is to put a severely battered Iran into an economic vise.”