Atwar Bahjat reported on Friday that the attack was part of an intense fire-fight.
"The assailants fired five mortar's shells on the central base of the Spanish, Salvadorian and US forces. The attack was followed by more than 15 minutes of armed confrontation while F-16 warplanes were hovering over the area.
Military officials in Najaf declined to give any details about the attack and the bulk of losses among the occupation forces.
"In Najaf, there were three bases, northern, central and southern. Occupation forces prevented journalists and reporters to approach these bases, they guarded and prevented travelling in the nearby area during the night," Aljazeera's Bahjat reported.
"At the same time, hundreds of Muqtada al-Sadr's supports gathered at the yard of thee shrine of Imam Ali, expressing support to al-Sadr amid US threats either to kill or arrest him", she added.
Witnesses in Najaf said a US convoy raided the city of Kufa where clashes erupted between US forces and Muqtada al-Sadr’s Mahdi militia.
Spanish Prime Minister José Luis Zapatero has said that the situation in Iraq continues to deteriorate and reiterated his election promise of returning Spanish troops unless UN mandate calls for an international force.