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."
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.