Washington (CNN) U.S. Navy warships will begin accompanying British-flagged commercial cargo vessels through the Strait of Hormuz, something they've already been doing with US-flagged vessels, Pentagon spokesman Col. Steve Warren announced Monday.

The accompanying of U.S. and British ships follows the seizure of a Marshall Islands-flagged vessel by Iranian Revolutionary Guard ships last week.

U.S. Navy warships have already begun escorting American vessels, accompanying four U.S.-flagged ships through the Strait of Hormuz Thursday. The new military operation offers armed protection from potential harassment by Iran's navy, a U.S. defense official told CNN.

All four unarmed U.S.-flagged vessels were military supply and survey ships either operated by the U.S. Military Sealift Command or under contract to the command. They traveled without incident.

The official said the Pentagon will not be providing daily details on transits or the warships in the area because the U.S. "does not want to establish a pattern of life" for observers in the area.

Col. Edward Thomas, special assistant for public affairs, said that "this is nothing more than benign but prudent accompanying of already scheduled ships."

He added that it was "not designed to send a signal" but is "merely a hedge against some unpredictable Iranian behavior the last few days."

The escorting, according to Thomas, is "not something we expect to continue for long."

CNN first reported Thursday that U.S. Navy warships would accompany U.S.-flagged commercial vessels that pass through the Strait of Hormuz due to concerns that ships from Iran's Revolutionary Guard Corps navy could try to seize a U.S. cargo ship.

Pentagon officials provided clarification Thursday afternoon that not every ship will necessarily be accompanied by the Navy. But this is still a significant change in the U.S. military posture in the Strait.

The classified plan was approved by the Pentagon earlier Thursday, according to a senior defense official.

While the Navy maintains a routine ship presence in the Persian Gulf and the North Arabian Sea, this new effort specifically requires an armed warship to be in the narrow channel between Iran and Oman when a U.S. commercial vessel passes through.

The decision to go ahead with this plan comes as Iran Revolutionary Guard ships harassed a U.S.-flagged vessel, the Maersk Kensington, on Friday and then later seized another cargo ship, the Maersk Tigris, flagged in the Marshall Islands.

The worry is that with the uncertainty around Iran's intentions, any seizure of a U.S.-flagged vessel could provoke an international incident with Iran.

"This is a way to reduce the risk of confrontation," the official told CNN.

The official emphasized the Navy is not trying to "play up" the current situation, but said the orders were approved "based on tensions in the region."

A second U.S. official said if it becomes necessary, U.S. warships are prepared to escort U.S. commercial vessels throughout the entire Gulf.

There are a number of U.S. ships and aircraft in the immediate vicinity, including four ships and several aircraft monitoring the status of the Marshall Island vessel, which remains in Iranian custody allegedly over a 2005 financial dispute. U.S. Navy ships will be moved in and out of the area depending on the transit schedule of U.S. cargo vessels.

Photos: Iran parades military equipment Iranian air force jets -- a MiG-29, from left, an F-4 Phantom and an F-14 Tomcat -- escort a Boeing 747 as they perform a flyover during a parade marking National Army Day on Saturday, April 18. Hide Caption 1 of 9 Photos: Iran parades military equipment Iranian army troops wearing ghillie camouflage suits participate in the parade just outside Tehran, Iran. Hide Caption 2 of 9 Photos: Iran parades military equipment Iranian President Hassan Rouhani reviews the parade April 18. Hide Caption 3 of 9 Photos: Iran parades military equipment Mid-range Zelzal missiles are driven through the parade outside Tehran. Hide Caption 4 of 9 Photos: Iran parades military equipment Soldiers drive a military vehicle through the parade. Hide Caption 5 of 9 Photos: Iran parades military equipment A Zoobin missile is exhibited during the parade. Hide Caption 6 of 9 Photos: Iran parades military equipment A soldier sits atop a T-72 tank as it rolls past a portrait of Supreme Leader Ayatollah Ali Khamenei on April 18. Hide Caption 7 of 9 Photos: Iran parades military equipment Missiles are paraded past Rouhani and military leaders. Hide Caption 8 of 9 Photos: Iran parades military equipment Iranian sailors march in the parade. Hide Caption 9 of 9

Iranian officials said the seizure of the Marshall Islands-flagged ship Maersk Tigris was due to a court decision.

Foreign Minister Mohammad Javad Zarif said Wednesday that the ship had "some rather peculiar activity" in its past that resulted in court action, according to lawyers with whom his ministry has been in touch.

"Simply, our naval forces implemented the decision of the court," he added.

Rickmers Shipmanagement, the company managing the Maersk Tigris, a Maersk Line ship, said in a statement Thursday that the apparent issue dates back to 2005, when another Maersk Line vessel delivered a shipment to Dubai that was later disposed of when no one collected the containers.

A spokesperson for Rickmers Shipmanagement also said that 24 people -- none American -- are on board the Maersk Tigris and that they are all doing well. However, the company continues to "insist that the crew and vessel are released as soon as possible."

The two recent incidents come after the U.S. last week sent warships to the vicinity of Yemen after concerns were raised that an Iranian convey was attempting to supply arms to Houthi rebels who have deposed the Western-backed government in Sanaa.

Multiple U.S. officials said the American ships had been deployed to the region to dissuade the Iranian convoy, which included armed ships, from docking in Yemen. The Iranian ships turned away from Yemen on Thursday.

The U.S. hope is that by deploying the naval accompaniment for cargo ships in the Strait of Hormuz, it's much less likely that Iran would cause trouble for them. Rather, like in the case of Yemen, they would be more inclined to turn back.

Still, the move comes amidst U.S.-Iran tensions in the region over competing interests in Yemen and elsewhere. And it also coincides with delicate nuclear talks in the which the United States and five other world powers are trying to seal a final deal with Iran curbing the latter's nuclear program.