Thousands of followers of radical cleric Muqtada al-Sadr took to Baghdad's streets following Friday prayers to protest a triple car bombing in one of their southern strongholds, in a show of strength directed at a rival Shi'ite powerbroker. On Wednesday, three car bombs went off in quick succession in Amarah, located in the Shi'ite heartland about 320 kilometers southeast of Baghdad. At least 25 people were killed and dozens wounded. No one has claimed responsibility. Car bombs are a hallmark of al-Qaida in Iraq, but the group is not known to operate there. However, the area, in Maysan province, has suffered from violent clashes between competing Shi'ite militias, including Sadr's Mahdi Army.