A senior officer in the Iranian Revolutionary Guard was recently killed in Syria by opposition rebels, according to reports Wednesday.

A man whose decapitated head had appeared in a photo five days previously was identified as IRGC Col. Mohammad Eskandari, according to a Syrian activist who goes by the pseudonym Charles Windsor (warning: graphic image).

Eskandari, who was listed in other reports as a brigadier general, was reportedly killed by the al-Qaeda-linked Al-Nusra Front, a rebel group that has been fighting to oust Syrian President Bashar Assad.

Windsor, who runs the Tharir Souri news network in Syria, which claims to provide unbiased reporting of the civil war, posted a photo of the decapitated head side by side with an unconfirmed photo of Eskandari taken at an unknown time or location.

The Iranian news agency ABNA also reported that Eskandari died in Syrian fighting, according to news and analysis website EA Worldview.

Earlier this month, Eskandari was quoted telling Iranian media that 42 divisions and 138 battalions of the elite IRGC were fighting in Syria, to bolster forces loyal to Assad.

Iran is one of Syrian President Bashar Assad’s main allies. Tehran has provided his government with military and political backing for years and has kept up its support since the uprising there began in March 2011.

Unconfirmed photo of Iranian Revolutionary Guard Corps Col. Mohammad Eskandari posted on the profile of Syrian activist who goes by the psuedonym Charles Windsor(screen capture: Facebook)

Unconfirmed photo of Iranian Revolutionary Guard Corps Col. Mohammad Eskandari posted on the profile of a Syrian activist who goes by the pseudonym Charles Windsor (Courtesy Facebook)

Eskandari added that “today’s war in Syria is really our war with America.”

In November, Iran’s semiofficial Mehr news agency reported that IRGC commander Mohammad Jamalhad been killed by “terrorists,” which is the term used by Iran and the Syrian regime for opposition forces.

In 2012, Guard chief commander Gen. Mohammad Ali Jafari said the IRGC had high-level advisers in Syria but it has denied it has fighters there.

The Associated Press contributed to this report.