Rescuers were searching for an Iraqi pilot who crashed his F-16 on a training mission in southeastern Arizona where the United States maintains a program for foreign military pilots.
U.S. officials said they could not identify the pilot, but confirmed he was an Iraqi.
A spokesman for the Iraqi defense minister identified the pilot as Brig. Gen. Rafid Mohammed Hassan.
"We have no word yet on his fate or the reason behind the crash," spokesman Brig. Gen. Tahseen Ibrahim told the Associated Press in Baghdad. "We are in contact with the Americans to get more details."
The plane, with its solo pilot, went down about 8 p.m. Wednesday in a rural area about five miles east of Douglas Municipal Airport, near the Mexican border, according to a spokeswoman for the 162nd Wing of the Arizona Air National Guard, which runs the training program for international pilots.
The crash about 120 miles southeast of Tucson started a fire that was initially blamed on a ruptured natural gas line. But military officials on Thursday said it was unknown whether gas was involved.
The Air Force has assembled an interim safety board to investigate the incident, the spokeswoman said.
The F-16 Fighting Falcon belongs to the Iraqi Air Force, part of two lots bought in 2011 and 2012. The purchases predate the recent air campaign in Iraq against the Islamic State.
Because of the difficult security situation, the craft were never sent to Iraq.
About 24 Iraqi Air Force pilots are in varying stages of the training program, which usually takes several years to complete. None of the Iraqis have graduated. The Arizona Air National Guard's 162nd Wing has been training international military pilots for 23 years.
"The 162nd is the 'face of the USAF to the world' providing the best-trained coalition war-fighting partners for the United States Air Force," the military wing says on its website. "The wing has trained pilots from 28 countries that fly the F-16 today while developing strategic partnerships and building strong international relationships based on performance, friendship and trust."
Currently, the 162nd Wing has about 40 students in training from Iraq, Singapore, Poland, Norway, Denmark, Oman, Belgium and the Netherlands, the spokeswoman said.