Gen. Ghodratollah Mansouri allegedly shot himself in the head by accident while cleaning his pistol, according to the Sunday report.
The report added that Mansouri was veteran of the 1980s Iran-Iraq war and a "defender of the shrine," a reference to Iranians who fight against the extremist Islamic State group in Syria and Iraq.
Since 2014, Mansouri was a regional commander of the Guard's ground forces in the northeastern city of Mashhad, some 900 kilometers east of the capital Tehran.
Hundreds of Iranian forces have been killed fighting IS in Syria and Iraq.
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