Al-Maliki had set a Wednesday deadline for "outlaws" in Maysan to hand in their weapons or face an offensive.

CNN: Iraq goes after Shiite militants near Iran

Some scholars have called the region located in and around Basra, Thiqar and Maysan provinces the biblical Garden of Eden.

CNN: U.N.: Iraq's marshlands recovering

Hours after the offensive began Thursday morning in Maysan, Iraq's Defense Ministry said 17 people had been detained, a weapons cache seized in Amara and weapons found near main roads and waterways.

CNN: Iraq goes after Shiite militants near Iran