WASHINGTON » Iran’s political and military elite boasted last month that their forces shot down a U.S. intelligence-gathering drone, a remotely piloted Navy vehicle called ScanEagle that they swiftly put on display for the Iranian news media.

Navy officials responded that no drones had been downed by enemy fire, although the Pentagon acknowledged that it had lost a small number of ScanEagles, likely to engine malfunction, over Afghanistan and in the Persian Gulf region. The drone the Iranians showcased appeared cobbled together after a crash — thus earning the nickname "FrankenEagle" across the Navy.

Regardless, the loss was hardly an intelligence coup for Iran, since ScanEagle carries only off-the-shelf video equipment with less computing power than can be found in a smartphone.

"They could have gone to RadioShack and captured the same ‘secret’ technology," said Vice Adm. Mark I. Fox, the Navy’s deputy chief for operations, plans and strategy.

The minor diplomatic contretemps over the fallen drone did, however, shine an unwanted light on the growing role of these relatively low-cost, nearly expendable unmanned surveillance aircraft in military operations over the Persian Gulf, as well as in North Africa and the Horn of Africa, and in the Asia-Pacific region.

A ScanEagle flying off the deck of the destroyer Bainbridge is credited with providing images critical to the ability of Navy SEAL snipers to identify and kill three hijackers holding hostage the captain of the Maersk Alabama off the coast of Africa in 2009. And a ScanEagle flying from the destroyer Mahan provided images of Libya in the first 72 hours of a North Africa mission by U.S. and NATO forces in 2011 to protect civilians and then support rebels who overthrew Moammar Gadhafi.

Most ScanEagles are owned and flown by contractors; some of these private crews are even based aboard U.S. warships. The drones are considered an important addition in the military’s surveillance architecture, which ranges from very costly spy satellites to advanced drones like Predators and Reapers, which carry advanced surveillance systems and can be armed with missiles, and down to the low-tech ScanEagle.

ScanEagles fly from two Navy ships in the Persian Gulf area, the Ponce and the Gunstan Hall, both amphibious support and staging vessels; they also fly from one ground operations center in the region established when a ScanEagle unit serving in Iraq was withdrawn as the mission there ended.

Since it can be launched on short notice, ScanEagle’s value is in allowing local commanders the ability to gather close-in, live and real-time images of an immediate target.

"Anybody who goes to sea is interested in having an understanding of the environment in which they are operating," Fox said. "These low-end assets give you an ability to have a much better understanding of what’s going on around you. Who’s in that dhow? What flag is it flying? But we are still in an early stage of it."

Navy officers say that adding another layer of surveillance aircraft to the U.S. fleet also has a deterrent effect on Iran.

"The fact that we are physically present with more and more intelligence, surveillance and reconnaissance assets — the Iranians know we are out there watching," said one officer familiar with ScanEagle deployments. "We are flying in international airspace and over international waters. But these assets give us ground truth on what everybody is doing in the gulf."

But the increased surveillance flights do carry a risk of provoking Tehran at a time of increased international tensions over its disputed nuclear program.

In November, Iranian warplanes shot at an Air Force surveillance drone flying over the Persian Gulf. Pentagon officials said the Predator was in international airspace and was not hit, and that the episode prompted a strong protest to the Iranian government. Iran said the Predator had violated their airspace.

And in late 2011, an RQ-170 surveillance drone operated by the CIA rather than the military crashed deep inside Iranian territory while on a mission that is believed to have been intended to map suspected nuclear sites. That episode came to light only after Iran bragged that it had hacked into the drone’s controls and guided it to a landing inside its borders. U.S. officials said the drone had crashed after a technical malfunction.

The ScanEagle, at the low end of the surveillance technology scale, can stay aloft for 24 hours, and at altitudes of up to 19,500 feet. It has a tiny engine — just 1.9 horsepower — but sufficient to carry the vehicle, four and a half feet long with a 10-foot wingspan, at a cruising speed of 48 knots. Built by Insitu, a Boeing subsidiary, the ScanEagle can carry a video camera with night vision and a thermal imaging system. It is unarmed.

The Defense Department fields about 250 ScanEagles across all of the armed forces, and the drone has logged 650,000 flight hours since it was first tested by the military in 2004.

While it is currently aboard a half-dozen warships, Navy officers expect that number to grow. Part of the push for ScanEagle is its relatively low cost, only $100,000 each.

Peter W. Singer, a senior fellow at the Brookings Institution, said the deployment of unmanned aircraft aboard Navy warships could be as revolutionary as the first introduction of conventional aircraft to the fleet.

"This is a game changer," Singer said. "Using remotely piloted vehicles in the framework of intelligence, surveillance and reconnaissance is just the first step."

Fitting missiles onto drones is already a proven asset for the military and the intelligence community, and the Navy might push the abilities even further, using drones — perhaps even jet-powered and refuelable in the air — to penetrate adversary air defenses for attack missions and for jamming communications and spoofing radar, he said.

In a time of tight budgets, though, Singer warned that the traditional flying communities in both the Navy and Air Force might push back against development and procurement programs that might take pilots out of the cockpit and put them in trailers to operate the aircraft remotely.

And he noted that what truly scares the pilot community is the possibility that technological advancements might allow future drone missions to be preprogrammed, perhaps even fully automatic — getting rid of a pilot altogether.