Protesters threw rocks and wrenched security cameras off the walls
Iraq's capital and south have been rocked by the worst street unrest since the 2003 US-led invasion with a protest movement venting fury at the govt and its backers in neighbouring Iran
Operations at the port have been at a complete standstill since Wednesday, after protesters first blocked its entrance on Tuesday.
Iraq accused IS of gathering civilians and then blowing up explosives-rigged vehicles nearby
Bridging operations under fire are complex but Iraqi forces have been trained by US military