Iran's Revolutionary Guards said Monday missiles it fired into Syria had successfully hit Islamic State group targets in retaliation for Tehran attacks claimed by the jihadists earlier this month.

"Based on credible information, the missile operation against Daesh has been successful," Revolutionary Guards spokesman General Ramezan Sharif said on the elite force's Sepahnews website, using an Arabic acronym for IS.

The Guards fired six missiles from the west of Iran across the border and into Syria's mostly IS-held Deir Ezzor province, targeting an IS command base, they said earlier.

Sunday's strike came after twin attacks in Tehran on June 7 killed 17 people, in the first attacks in the Islamic republic claimed by IS.

The missile attack was the first by Iran outside its own territory in 30 years, since the Iran-Iraq war of 1980-88, media in the Islamic republic has reported.

General Amir Ali Hajizadeh, who heads the Revolutionary Guards' aerospace wing, told state television: "The missiles were fired from Iran and they passed over Iraq and landed in Syria."

"Drones flying from near Damascus to Deir Ezzor transmitted (footage of) missiles hitting their targets," he said.

"Firing these missiles from 600 or 700 kilometres away onto a small building... demonstrates Iran's capacity and intelligence capabilities" against jihadist groups, he said.

It came hours after supreme leader Ayatollah Ali Khamenei in a statement vowed Iran would "slap its enemies" in honour of the families of victims, including those killed in Syria and Iraq.

Iranian media reported some of the mid-range missiles fired into Syria were of the Zolfaghar type, a precision-guided missile with a range of about 750 kilometres. 

Iran's homegrown missiles, a serious point of contention with Washington and Tel Aviv, can reach up to 2,000 kilometres.

Source: AFP