A top Iranian official claimed on Sunday that his government was copying a top-secret American spy drone captured by Iran’s armed forced last year.

General Amir Ali Hajizadeh, who is chief of the aerospace division of the powerful Revolutionary Guards, was quoted by a semi-official news agency as saying that Iranian experts are recovering information from the U.S. RQ-170 Sentinel captured in December in eastern Iran, al Arabiya News reported.

“There is almost no part hidden to us in this aircraft. We recovered part of the data that had been erased. There were many codes and characters. But we deciphered them by the grace of God,” Hajizadeh said.