BAGHDAD (AFP) - The Islamic State in Iraq and Syria (ISIS) group has claimed the killing of a senior Iranian officer advising Iraqi forces in their fight against the extremists, according to images posted on extremist forums Monday.

Iran's Revolutionary Guards on Sunday announced the death of Brigadier General Hamid Taghavi, who had been training the army and Iraqi volunteers in the city of Samarra, north of Baghdad.

One extremist forum posted an image of the officer standing next to three others, with a red circle around his head above the caption: "A photo of the miscreant Hamid Taghavi who was killed by the men of ISIS in the region of Samarra." Another image on the forum purportedly showed the body of the Iranian officer.

ISIS has not said how Taghavi died, but his funeral was held in Teheran on Monday in the presence of several senior officials.

"If people like the martyr Taghavi were not engaged in Syria and Iraq against the terrorists, the enemy would surely look to create insecurity in our country," Supreme National Security Council secretary Ali Shamkhani told funeral goers, the official Fars news agency reported.

Shi'ite Iran has sent military advisers to Iraq to help train and equip army troops and allied militias in their counteroffensive against ISIS, a hardline Sunni Islam group which seized large areas of the country in a June assault.

It has also armed Kurdish forces in northern Iraq and Iranian media have reported the deaths of several military personnel in both Iraq and Syria this year.

Iran is not participating in a US-led coalition conducting air strikes against ISIS positions in Iraq and neighbouring Syria.

Samarra, 110 kilometres north of Baghdad, is a mainly Sunni city but also home to the Askari shrine, one of the holiest sites in Shi'ite Islam.

Several Iranian officials, including President Hassan Rouhani, have declared the preservation of Iraqi Shi'ite sites a "red line".