US Defense Secretary Leon Panetta on Monday dismissed claims by Iran that it had gleaned data from a downed US drone and was now building a copy of the robotic spycraft.

"I can tell you from my experience that I would seriously question their ability to do what they said they've done," Panetta, a former CIA director, told reporters before landing in Bogota.

The commander of the Iranian Revolutionary Guards' aerospatial division, General Amir Ali Hajizadeh, said on Sunday that Iran had discovered "codes" from the bat-winged RQ-170 Sentinel that fell into Tehran's hands in December.

Panetta scoffed at Iran's account but said he could not discuss details of such a sensitive subject.

"It's, obviously, a classified program. I don't want to get into the particulars," he said during a briefing on his flight to Bogota, at the start of a Latin American tour.

Iran's gleeful military proudly displayed the unmanned Sentinel drone on state television apparently intact, though with what appeared to be damage to one of its wings.

Iran claimed one of its cyberwarfare team hacked the drone's controls by confusing its GPS guidance system, and has since claimed it would reverse-engineer the drone.

US officials acknowledged losing the drone on a spying mission over Iran, but asserted the stealth aircraft came down because of a technical problem, not any Iranian intervention.

Panetta, in his first visit to Latin America as Pentagon chief, said the United States was concerned about the Guards' alleged attempts to expand their influence in the Middle East as well as in South America.

"That in my book relates to expanding terrorism, and I think that's one of the areas we're all concerned about," he said.

Speaking later at a joint press conference in Bogota with his Colombian counterpart Juan Carlos Pinzon, the US defense secretary announced the sale of 10 military helicopters to Colombia, including five Black Hawks, to help the government in its fight with FARC leftist rebels.