Shafaq News/ Iraq's powerful Shiite cleric Muqtada al-Sadr on Sunday called for an "immediate investigation" into the landslide that hit the Qattara of al-Imam Ali shrine, which is in a natural depression.

"Once again, corruption suspicions leave civil victims in al-Qattara. However, this time corruption impacted house of worship," al-Sadr tweeted.

"We offer our condolences to the families of the victims. We ask God to beseech them with patience and solace," he said, "we demand the government for an immediate and serious investigation in order to reveal the truth so that corruption does not affect mosques and places of worship, as it affected state institutions and ministries."

Rescuers in the Iraqi governorate of Karbala have retrieved five bodies from rubble after a roof collapse at a Shia shrine, including one child.

They had earlier said they were struggling to retrieve "between six and eight people" who were still believed to be trapped under rubble.

"We have found four bodies, including that of a woman" at the site about 25km from the holy city of Karbala, central Iraq, civil defence official Abdelrahman Jawdat told AFP.

Later, Jawdat announced a fifth body had been retrieved. 

"That could be the final toll," he added, while digging continued in case there were other victims.

"Saturation of the earthen embankment adjacent to the shrine" due to humidity caused the slide, the civil defence told the official Iraqi News Agency.

"This led to the collapse of about 30 percent of the area of the building, which measures about 100 square metres," he said.

Emergency services said that three children had been rescued by Saturday afternoon and they were in "good condition" in hospital.

INA said teams had been working through the night under floodlights to provide supplies of oxygen as well as food and water to people trapped through gaps in the rubble.

A number of Iraqi politicians responded to the rescue effort, praising the team involved.

"We ask God Almighty for a speedy recovery for the injured and patience and strength for those under the rubble and we pray for quick efforts to save them," tweeted Qais al-Khazali, the head of the Asaib Ahl al-Haq organisation.

Prime Minister Mustafa al-Kadhimi also tweeted that he was in touch with the workers.

"In a telephone conversation with the governor of Karbala and its officials, Mr Kadhimi stressed the importance of making immediate efforts by the rescue teams in the civil defence, and performing the duty in the fullest manner," his office tweeted.