TEHRAN/WASHINGTON/LONDON/NEW DELHI - The Navy of Iran's Islamic Revolution Guards Corps (IRGC) said that the Strait of Hormuz has been blocked since Saturday evening and will not reopen until the United States lifts its naval blockade on the waterway.

In a statement carried by its official news outlet Sepah News, the IGRC said that the move came after the United States violated its commitments under the two-week ceasefire, which took effect on April 8, and failed to end its naval blockade against Iranian vessels and ports.

The IRGC Navy called on all vessels and their owners to follow official updates via its channel and VHF Channel 16, the international maritime distress, safety, and calling frequency. The statements by US President Donald Trump hold no credibility in the strait and the Gulf, it added.

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The IRGC warned that no vessel should move from its anchorage in the Gulf or the Gulf of Oman, and any approach to the strait would be deemed "cooperation with the enemy" and targeted accordingly.

Iran had tightened control over the strait since Feb 28, when it barred passage to vessels belonging to or affiliated with Israel and the United States after the two countries' joint strikes on Iranian territory. The United States later imposed its own blockade on the waterway after peace negotiations with Iran in Pakistan's Islamabad collapsed.

On Friday, Iranian Foreign Minister Seyed Abbas Araghchi said the strait would remain "completely open" to commercial shipping during the current truce with the United States, in line with the announcement of the ceasefire in Lebanon.

However, Trump said Friday the US naval blockade would "remain in full force," noting that the United States would not lift it until the country makes a deal with Iran. He then said Saturday that Iran cannot "blackmail" the United States with the strait.

"We're talking to them. They wanted to close up the strait again... and they can't blackmail us," Trump said at an event in the White House.

READ MORE: Trump says Iran conflict could end 'pretty soon'

Iran's Supreme National Security Council said on Saturday that the country is determined to control traffic through the Strait of Hormuz until the war is definitively ended and lasting peace is achieved in the region.

As long as the enemy intends to disrupt the passage of vessels and employ methods such as naval blockade, Iran will consider this a violation of the ceasefire and will prevent the conditional and limited opening of the strait, it said.

Vessel tracking data showed that around 10 ships turned back on Saturday while attempting to pass through the waterway, following Tehran's renewed control over it.

WSJ: US military prepares to board Iran-linked ships

Citing US officials, The Wall Street Journal on Saturday reported US military is preparing in the coming days to board Iran-linked oil tankers and seize commercial ships in international waters.

The US "will actively pursue any Iranian-flagged vessel or any vessel attempting to provide material support to Iran," Dan Caine, chairman of the Joint Chiefs of Staff, said Thursday.

The move will enable the US to take control of Iran-linked vessels around the world, including ships carrying Iranian oil that are already sailing outside the Persian Gulf and those carrying arms that could support Tehran, the report said.

The operation would be carried out in part by the US Indo-Pacific Command, according to Caine.

UKMTO: 3 incidents in Hormuz Strait

Also on Saturday, three separate maritime security incidents involving commercial vessels were reported in waters near the Strait of Hormuz within three hours, according to the latest daily summary released by the UK Maritime Trade Operations (UKMTO) agency.

UKMTO said the regional security environment remains volatile, with ongoing military activity continuing to pose risks to commercial shipping.

In the first incident, a tanker was approached by two IRGC gunboats about 20 nautical miles northeast of Oman. The master reported that the vessels opened fire on the tanker without issuing a prior VHF radio challenge. The tanker and all crew members were reported safe.

READ MORE: Mediators push diplomacy as Iran port blockade continues

In the second incident, a container ship was struck by an unknown projectile about 25 nautical miles northeast of Oman, with several containers on board damaged.

No fires or environmental impact were reported.

In the third incident, a commercial vessel reported seeing a splash in close proximity to the ship while transiting about three nautical miles east of Oman. No further details on damage or threat were immediately available.

India conveys concern

India on Saturday expressed its deep concern at the shooting incident involving two Indian-flagged ships in the Strait of Hormuz, said the country's Ministry of External Affairs (MEA) in an official statement.

According to the statement, the MEA summoned Iranian Ambassador to India Mohammad Fathali for a meeting with the country's Foreign Secretary Vikram Misri to convey India's concern.

Misri noted the importance that India attached to the safety of merchant shipping and mariners and recalled that Iran had earlier facilitated the safe passage of several ships bound for India.