A senior officer of Iran's Islamic Revolutionary Guard Corps was killed in Syria on Monday.
The officer, who was named as Gen Abolfazl Alijani, was a member of the IRGC’s Ground forces, the semi-official Iranian news agency Mehr reported.
"Gen Alijani was martyred on Monday while serving as a military adviser in the country," Mehr reported.
No further details were given about the officer or the causes of his death.
His body is to be taken to Iran in the coming days for his funeral.
The IRGC often announces the deaths of some of its members in "the line of duty" in Syria.
Since it began its mission to support Syrian President Bashar Al Assad in the civil war, Iran has increasingly reported casualties.
Earlier this month Iran held funerals for five IRGC officers killed in Syria, highlighting the human cost of its involvement in the war.
Thousands of Iranians gathered in Tehran’s streets waving red flags to mark Ashura in early August, a commemoration of the seventh-century death of the Prophet Mohammed’s grandson Hussein, a revered figure in Shiite Islam.
They chanted “Death to America” and “Death to Israel” as Iran has previously blamed Israeli strikes for the death of its military officials.
Iran responded by vowing to avenge their deaths.
Both Iran and Russia have provided financial and military support to Mr Al Assad's regime since Syria's conflict began in 2011.
Iran has a presence on the ground while Russia introduced an air campaign that has helped Mr Al Assad recover control over most of the country more than 10 years after the war started.
Tehran says it has stationed its forces in Syria at the invitation of Damascus and only as advisers.
The conflict in Syria started with the brutal repression of peaceful protests before escalating and drawing in foreign powers and global extremists.
The war has killed at least 500,000 people.