Any crackdown on mobile communications would add a new dimension to the conflict for the ‌thousands of U.S. troops in the region, many of whom still rely on phones to periodically message loved ones and assure them they are well.

Admiral Brad Cooper, in a previously unreported letter, said Iran was benefiting from being able to see the success or failure of its strikes in near real-time by searching news reports or online posts by journalists referencing "reactions, photos, and footage from the cellphones of our troops."

"The direct, unavoidable cost of this open-source intelligence could be measured in the lives of ​American service members and civilian residents in targeted Gulf countries," Cooper, head of U.S. Central Command, wrote in his July 28 letter, a copy of which was obtained by Reuters.

He called on troops to "redouble ​our focus on operational security," without prescribing specific steps in the memo.

The warning underscored the mounting tensions between real-time news reporting on the war, often aided ⁠by satellite imagery and first-person accounts, and the desire by the U.S. military to restrict any information that could aid Iran as it tries to kill and wound U.S. troops.

In Jordan, which has been a frequent ​target of Iranian strikes, some troops have been told their phones will be confiscated in the coming days, two sources familiar with the matter told Reuters.

A third source said such a move was being considered in ​the region due to operational security concerns but did not present the confiscation as a certainty.

Asked for comment, U.S. Central Command spokesperson Captain Timothy Hawkins said: "The message is a general reminder to our service members on the importance of maintaining operational security. This is one of many opportunities Admiral Cooper has used to convey operational priorities."

RUNNING FOR SHELTER DURING IRAN ATTACK

In a video posted online this month, a U.S. service member recorded a video as soldiers ran for shelter during a deadly ​Iranian attack on the Muwaffaq Salti Air Base in Jordan on July 17.

Cooper appeared to reference the footage in his letter, saying it had been recorded on Meta smart glasses with a built-in camera.

"Video captured ​from a service member's Meta glasses was posted on Instagram showing where and how the individual had evacuated to a bunker during an Iranian missile and drone attack," Cooper wrote.

Iran would normally have a tough time determining the success ‌or failure of ⁠its strikes, were it not for such accounts, Cooper said, thanks to the U.S. military's electronic jamming or other tactics used in war zones.

"Iran knows the weapons were fired; however, their forces do not know if they missed by 50 meters, hit an empty tarmac, or successfully struck a crowded facility," he wrote. "Detailed lists, descriptions, and analyses of what was hit, openly published by news outlets are essentially performing Iran’s Battle Damage Assessment (BDA) for them, free of charge," Cooper said.

Some 18 U.S. troops have died in the conflict with Iran that started on Feb. 28 and more than 600 have been wounded in the fighting, casualties that have deepened ​Americans' concerns about a war that just one in three ​Americans support.

Democratic lawmakers have called for more information ⁠about the war, including details about damage to U.S. infrastructure on bases including radar towers, barracks and aircraft hangars. They have also called for the release of a U.S. military investigation into a likely U.S. strike on a girls' school in Iran, first reported by Reuters, on the opening day of the war on Feb. 28.

CELL ​PHONES BEING TAKEN?

Rules surrounding cell phone use for deployed troops can vary widely across the military, officials say. Many troops have to lock them away ​and cell phones can be ⁠banned on particularly sensitive missions by special operations forces, for example.

But the possible seizure of phones has stoked anxiety among some family members, already on edge in recent months as they read Iranian claims of deadly strikes on bases throughout the Middle East, two of the sources said.

U.S. officials have cautioned for years that certain applications on mobile devices, like fitness applications, can be exploited by adversaries to aid adversary targeting because of location data. Reuters reported in ⁠May that commercially available ​location data harvested from smartphones or other devices has been used to target or surveil U.S. forces.

At the same time, the ​Pentagon has sought to carefully control the release of information due to what it says are operational security concerns, often declining to comment on Iran's attack claims or detail individual incidents that led to injuries of U.S. troops.

Cooper said details on strikes can help Iran ​mount follow-up attacks.

"Detailed public disclosures can become an immediate green light for Iranian forces to launch a secondary, much more devastating wave of attacks," he said.