A security source in the Salahuddin province, where Samarra is located, was quoted by Alsumaria news agency as saying that the Saraya al-Salam fighters foiled the attack when the ISIL terrorists tried to raid the town from the western side.
The source, speaking on condition of anonymity, noted that the assailants suffered heavy losses in a counterattack.
Iraq has been facing the growing threat of terrorism, mainly posed by the ISIL terrorist group.
The ISIL militants made advances in northern and western Iraq over summer 2014, after capturing swaths of northern Syria.
However, a combination of concentrated attacks by the Iraqi military and the volunteer forces, who rushed to take arms after top Iraqi cleric Ayatollah Ali al-Sistani issued a fatwa calling for fight against the militants, have blunted the edge of the ISIL offensive.