Baghdad ? Followers of anti-U.S. Shiite cleric Muqtada al-Sadr denounced the American military’s construction of a concrete wall through their Sadr City stronghold in Baghdad, the scene of renewed clashes Friday between his militiamen and U.S. and Iraqi troops.

The wall – a concrete barrier of varying height up to about 12 feet – is being built along a main street dividing the southern portion of Sadr City from the northern, where al-Sadr’s Mahdi Army fighters are concentrated.

American commanders hope that construction of the Sadr City wall, which began Tuesday, will effectively cut off insurgents’ ability to move freely into the rest of Baghdad and hamper their ability to fire rockets and mortars at the Green Zone, the central Baghdad district where government offices and the U.S. Embassy are located.