Iran tightens control of Strait of Hormuz, Trump warns against ‘blackmail’

Reuters-April 18th2026

By Trevor Hunnicutt, Ariba Shahid and Muhammad Al Gebaly

WASHINGTON/ISLAMABAD, April 18 (Reuters) – Iran said it was tightening control over the Strait of Hormuz on Saturday, warning mariners the vital energy route was again closed, but President Donald Trump said Tehran could not blackmail the United States by shutting the waterway.

Tehran said it was responding to a continued U.S. blockade of Iranian ports, calling it a violation of their ceasefire, while Supreme Leader Mojtaba Khamenei said Iran’s navy ‌was ready to inflict “new bitter defeats” on its enemies.

Shipping sources said at least two vessels reported coming under fire and being hit while trying to transit the waterway. India later said the Iranian ambassador in New Delhi had been summoned and that it had expressed deep concern to him that two Indian-flagged ships had come under fire in the strait.

State media in Iran quoted the Supreme National Security Council as saying Iranian control over the strait included demanding the payment of costs related to security, safety and environmental protection services.

State television also quoted the Supreme National Security Council as saying the U.S. had put forward new proposals after talks mediated by Pakistan in recent days. Tehran was considering them but had not yet responded, it said.

There was no immediate sign of direct U.S.-Iran talks taking place at the weekend, despite Trump saying on Friday that negotiations would take place.

UNCERTAINTY AROUND IRAN CONFLICT

Tehran’s renewed tough messaging caused fresh ⁠uncertainty around the Iran conflict, raising the risk that oil and gas shipments through the strait could remain disrupted just as Washington weighs whether to extend the fragile ceasefire.

Trump said the U.S. was having “very good conversations” with Iran but that Tehran wanted to close the strait again. Iran could not blackmail the U.S., he said.

Maritime security and shipping sources said some merchant vessels had received radio messages from Iran’s navy saying no ships were allowed through the waterway, reversing Friday’s signs that traffic might resume.

Maritime trackers had earlier shown a convoy of eight tankers transiting the narrow passage in the first major movement of ships since the U.S.-Israeli war on Iran began seven weeks ago.

Hours earlier, Trump had cited “some pretty good news” about Iran, declining to elaborate. But he also said fighting might resume without a peace deal by Wednesday, when the two-week ceasefire expires.

Iran had announced its temporary reopening of the Strait of Hormuz following a separate U.S.-brokered 10-day ceasefire agreement on Thursday between Israel and Lebanon. Israel invaded parts of southern Lebanon after the Iran-allied Hezbollah militant group joined the fighting in early March.

But on Saturday Iran’s armed forces command said transit through the strait had reverted to a state of strict Iranian military control, citing what it described as repeated U.S. violations and acts of “piracy” under the guise of a blockade.

The spokesperson said Iran had earlier agreed, “in good faith,” to the managed passage of a limited number of oil tankers and commercial vessels following negotiations, but said continued U.S. actions had ‌forced Tehran ⁠to restore tighter controls on shipping through the strategic chokepoint.