Iran has captured another U.S. drone, the country's state-run Fars news agency reported overnight.

Ali Fadavi, commander of the naval branch of the Iranian Revolutionary Guards, told Press TV (another state-run outlet) that the Scan Eagle Unmanned Aerial Vehicle was conducting a reconnaissance flight over the Persian Gulf when it entered Iranian air space and was captured.

Fadavi's claim, and the Iranian footage, could be bunk. Even if the captured robot is real, it's not clear whether it crashed or was somehow forced down. Cmdr. Jason Salata, a Navy spokesman, told the AP that all U.S. drones were "fully accounted for." However, he did say that some Scan Eagles have been lost at sea in the past.

The alleged drone capture comes just a month after Iranian jets tried and failed to shoot down an American Predator UAV – and almost exactly a year after getting its hands on a stealthy U.S. Air Force Sentinel drone that crashed, or was hijacked, on the Iran-Afghanistan border.

As was the case with the admittedly secretive Sentinel, Iran stands to gain little from examining and even disassembling one of the 40-pound, catapult-launched Scan Eagles, fairly basic UAVs built by Boeing and Insitu. Whether real or faked, however, the supposed capture is indicative of the ramp-up in U.S. robotic surveillance tied to increasing concern over Iran's nuclear program.

U.S. officials told The Wall Street Journal this week that Washington has "significantly stepped up" surveillance of Iran's coastal Bushehr nuclear power plant beginning in October, when Tehran's engineers unexpectedly removed two weapons-grade plutonium rods from the brand-new facility.

Iranian officials justified the November attack on the Predator drone by claiming the robot was spying on Bushehr, a claim the U.S. has denied. The unarmed Predator was reportedly flying 16 miles off the Iranian coast; Iran's airspace extends just 12 miles.

Likewise, it's widely believed the Afghanistan-based Sentinel was also gathering data on Iranian nuclear enrichment when it went down.

The diminutive Scan Eagle, however, is ill-suited to that kind of strategic reconnaissance. Instead, it's more of a tactical system meant to extend the visual range of ships, commando forces and air base defenders. Scan Eagles have flown recon for Navy SEAL raids in Somalia. A Scan Eagle kept tabs on the cargo ship Maersk Alabama after pirates kidnapped the vessel's captain in 2009. The boomerang-shaped 'bots patrol the perimeter of Bagram Air Field in Afghanistan.

Just four feet long, the camera-equipped Scan Eagle flies low and slow – barely 80 miles per hour. It navigates autonomously following pre-programmed GPS waypoints for up to 24 hours, but generally stays within 100 miles of its operators so that it can relay video via line-of-sight radio.

After the ubiquitous, hand-thrown Raven, the Scan Eagle is one of the most common drones in the world, (.pdf) with more than 1,000 in use by military and scientific agencies. It was originally designed to help fishermen track schools of tuna and, in its standard model, contains no secret technology. The Air Force and Boeing-Insitu didn't hesitate to show me around their Scan Eagle unit in Afghanistan.

Iranian commander Fadavi said the downed Scan Eagle had been launched by a U.S. aircraft carrier. It's true the Americans have a flattop in the region: the USS John C. Stennis. But carriers do not routinely deploy the catapult and tower-mounted hook for launching and landing Scan Eagles, as they could interfere with regular flight ops.

But that doesn't mean the Scan Eagle couldn't have come from the sea. The tiny drone is compatible with Navy destroyers, amphibious ships and patrol boats and is also launched by the Ponce, the Navy's floating Persian Gulf staging base for minehunters, boats and Special Operations Forces. With as many as 22 Scan Eagles in the air at any given time, according to Boeing, the U.S. could virtually swarm the Iranian coast with the small flying robots, if it wished.

But the vital intel work isn't being done by Scan Eagles. That's a job for Sentinels and other stealthy systems. In claiming to capture one of the much smaller Boeing-Insitu drones, Iran proves nothing we didn't already know – and prevents none of the real spying on Tehran's nuclear facilities.