Local medical sources from the health directorate in Babil province told Anadolu Agency -- on condition of anonymity due to restrictions on speaking to media -- that the hospitals in the area had received at least 75 dead bodies, adding another 45 were injured.
The blast reportedly occurred as buses carrying Iranian and Iraqi visitors were waiting at a gas station.
A large number of deaths and injuries were of Iranian visitors, the medical sources said.
Hundreds of thousands of Iranians come to Iraq each year to visit holy Shia shrines and attend religious ceremonies.
The terrorist group Daesh took responsibility for the attack on websites sympathetic to the group.
Turkey condemns terror attack in Iraq
Turkey "strongly" condemned the terror attack in Iraq’s Babil province that left at least 75 people dead.
In statement issued on Thursday, the Foreign Ministry said Turkey conveyed its condolences to the relatives of those who lost their lives.