The rockets fell near the Kawergosk refinery, one of the largest in the oil-rich area, located about 20 kilometres (12 miles) northwest of regional capital Arbil, the forces said in a statement.

"The rockets were launched from Khazir area in Mosul," Iraq's second city, located to the west of Arbil, the statement added.

The attack was not immediately claimed.

It comes less than a month after Iran's Revolutionary Guards -- the Islamic republic's ideological army -- claimed an assault on Arbil that it said targeted an Israeli "strategic centre".

The Guards fired a dozen ballistic missiles in the March 13 attack, which caused extensive damage to buildings without resulting in any deaths.

Kurdish authorities have insisted the Jewish state has no sites in or near Arbil.