Iraq launched an air strike on an Islamic State group target inside neighbouring Syria on Thursday, the military said.

F-16 fighter jets destroyed a building where members of the ultra-hardline Sunni group's leadership were operating, it said in a statement.

Islamic State group, which once occupied a third of Iraq's territory, has been largely defeated in the country but still poses a threat along its border with Syria.

"Iraqi F-16 jets bombed this morning on Thursday a so-called command and control centre containing leaders and fighters belonging to the Daesh (Islamic State group) terrorist gang in the Hajin inside Syrian territory," the statement said.

The Iraqi air force has carried out several air strikes against Islamic State group in Syria since last year, with the approval of the Syrian government of President Bashar al-Assad and the US-led coalition fighting Islamic State group.

Iraq has good relations with Iran and Russia, Assad's main backers in the Syrian civil war, while also enjoying strong support from the US-led coalition.

Prime Minister Haider al-Abadi declared final victory over Islamic State group in December but it still operates from pockets along the border with Syria and has continued to carry out ambushes, assassinations and bombings across Iraq.

Islamic State group  has resorted to guerrilla tactics since it abandoned its goal of holding territory and creating a self-sufficient caliphate that straddles Iraq and Syria.