From the Associated Press, apparently the New Orleans police shot at eight people carrying guns on the Danziger bridge, killing five or six of them.
There is a rumor that these people were contractors, but I have so far been unable to verify or falsify the rumor.
Update: It seems that the people shot at were not contractors, but those who had shot at the contractors:
As authorities struggled to keep order, police shot and killed at least five people Sunday after gunmen opened fire on a group of contractors traveling across a bridge on their way to make repairs, Deputy Police Chief W.J. Riley said.
Fourteen contractors were traveling across the Danziger Bridge under police escort when they came under fire, said John Hall, a spokesman for the Army Corps of Engineers. None of the contractors was killed, Hall said.
The bridge spans a canal connecting Lake Pontchartrain and the Mississippi River.
No other details, including whether any of the gunmen were killed, were immediately available.