A U.S. Air Force F-16 Fighting Falcon jet crashed over northwestern Arizona on Thursday morning. The condition of the pilot was not immediately known.

A preliminary investigation has already been set up to find out what happened to the jet, which took off earlier that morning from 56th Fighter Wing at Luke Air Force Base.

"Luke AFB officials are working closely with local authorities in a search and rescue operation," Luke said in a news release Thursday afternoon. "Due to the remote location and rugged terrain, the status of the pilot is unknown."

According to military officials, the jet crashed around 8:45 a.m. local time near the town of Bagdad. 

The F-16 first launched in 1976 and is famed for its capability and maneuverability in air-to-air and air-to-ground combat. The Fighting Falcon played a key role in the recent wars in Iraq and Afghanistan. 

Manufacturer General Dynamics had built more than 4,500 since the 1970s and is still taking orders from abroad while continuing to maintain the large U.S. force that recently had its operational life extended beyond 2025. The F-16 was supposed to be replaced by the incoming F-35 jet, but delays and concerns over operational ability of the Lockheed Martin-built aircraft means the Navy and Air Force will operate the Fighting Falcon long past its estimated expiration date.

While the ageing aircraft has generally had a good safety record, only recording four major incidents between 1975 and 2003, in 2015 it suffered two crashes and one collision leading to the death of 13 military personnel and civilians.

Pakistan, which has bought around 70 F-16s since the 1980s, recently had its order of eight blocked by Congress over fears that the lethal aircraft would be used against civilians or used in a conflict with India. Pakistan has appealed to Congress over the denial.