WASHINGTON — Iran is building a nonworking mock-up of an American nuclear-powered aircraft carrier that United States officials say may be intended to be blown up for propaganda value.

Intelligence analysts studying satellite photos of Iranian military installations first noticed the vessel rising from the Gachin shipyard, near Bandar Abbas on the Persian Gulf, last summer. The ship has the same distinctive shape and style of the Navy’s Nimitz-class carriers, as well as the Nimitz’s number 68 neatly painted in white near the bow. Mock aircraft can be seen on the flight deck.

The Iranian mock-up, which American officials described as more like a barge than a warship, has no nuclear propulsion system and is only about two-thirds the length of a typical 1,100-foot-long Navy carrier. Intelligence officials do not believe that Iran is capable of building an actual aircraft carrier.

“Based on our observations, this is not a functioning aircraft carrier; it’s a large barge built to look like an aircraft carrier,” said Cmdr. Jason Salata, a spokesman for the Navy’s Fifth Fleet in Bahrain, across the Persian Gulf from Iran. “We’re not sure what Iran hopes to gain by building this. If it is a big propaganda piece, to what end?”