The deaths bring to 33 the total number of armed men that US forces say they have killed in Baghdad on Thursday and Friday.
Fighting has flared in Baghdad since Nuri al-Maliki, the Iraqi prime minister, ordered a crackdown on militias in late March.
Most fighting has been concentrated in and around Sadr City, where two million people are caught in a battle zone.
Aid workers have warned of a looming humanitarian crisis as trapped civilians are running out of food, water and medicines.
Al-Sadr threatened last month to scrap a truce he imposed on his Mehdi Army militia in August.
A few weeks later, he urged them to continue to observe the ceasefire, leaving Iraqis guessing over his intentions.
But clashes in Baghdad have continued every day, raising questions over the control Sadr has over those claiming allegiance to him and to what extent he wants to end the conflict.