The US Air Force has grounded its entire fleet of F-15 fighter jets after a jet crashed on a training mission in Missouri last week.
F-15s have been involved in several crashes recently
Use of the planes will be restricted until a possible structural failure in the aircraft has been investigated, an air force spokesman said.
The Air Force has 676 F-15s in service, including a number in Afghanistan.
F-15s have had several accidents this year, although the current suspension is linked only to last week's crash.
Preliminary inquiries suggest that the F-15 may have been affected by a mechanical failure.
The plane belonged to the Missouri Air National Guard and was being used in a training exercise when it crashed near the city of Salem, Missouri.
It is thought that the plane, which dated from 1980, started to break up in the air. The pilot ejected, suffering a broken arm and minor cuts and bruises.
The Air Force now says hundreds of jets are to undergo urgent safety checks, including those on mission in Afghanistan. The planes are no longer used in Iraq.
Orders to ground an entire fleet of planes are not common. Air Force spokeswoman Jennifer Bently said that she did not know when the step had last been taken.
Although the decision to ground the F-15s was based solely on the Missouri crash, the jets have been involved in three other accidents in recent months.
F-15s have been a mainstay of US air power since 1975, but the Air Force stopped buying them in 2004, intending to replace them gradually with the more up-to-date F-22 Raptor, made by Lockheed Martin.
Boeing - the manufacturer of the F-15 - is still producing them for other customers.