TEHRAN, Iran (AP) — A senior Iranian commander says the country has reverse-engineered an American spy drone captured by Tehran’s armed forces last year and has begun building a copy.

Gen. Amir Ali Hajizadeh, who is chief of the aerospace division of the powerful Revolutionary Guards, was quoted Sunday by the semi-official Mehr news agency as saying that experts are also recovering data from the U.S. RQ-170 Sentinel captured in December in eastern Iran.

U.S. officials have acknowledged losing the drone. They have said Iran will find it hard to exploit any data and technology aboard it because of measures taken to limit the intelligence value of drones operating over hostile territory.