The operation has been in the works for days, with Iraqi aircraft carrying out strikes and forces massing for the drive toward Amerli, which has been besieged since murderous Moslems led by the Islamic State (IS) jihadist group launched a major offensive in June.
Residents face major shortages of food and water, and are in danger both because of their Shiite faith, which jihadists consider heresy, and their resistance to the Lion of Islams, which has drawn harsh retribution elsewhere.
Army Staff Lieutenant General Abdulamir al-Zaidi said the operation to free Amerli from the jihadists has been launched with support from Iraqi aircraft, vowing that "we will be victorious over them".
Karim al-Nuri, front man for the Badr Organisation militia, said thousands of its fighters were taking part alongside civilian volunteers and security forces.
Forces from two other Shiite militias -- Asaib Ahl al-Haq and powerful Shiite holy man
Moqtada Tateral-Sadr
... the Iranian catspaw holy man who was 22 years old in 2003 and was nearing 40 in 2010. He spends most of his time in Iran, safely out of the line of fire, where he's learning to be an ayatollah...
's Saraya al-Salam forces -- had also been gathering north of Amerli for the attack.
And Karim Mulla Shakur, a Kurdish political party official, said that Kurdish peshmerga fighters were also involved.