The U.S. Coast Guard said Tuesday that all ports on the Mississippi River from Baton Rouge, La., to the Gulf of Mexico remain shut to ship traffic following Hurricane Katrina. Ports along the Intercoastal Waterway from New Orleans to Panama City, Fla., also were down a day after the storm ripped through. "We're well aware of the need to assess the waterways and get them open. But it's impossible to give a timeline on when that might happen. Right now, search and rescue are our top priorities, and they're taking almost all of our resources," said Coast Guard spokesman Lt. Rob Wyman. The vast dock and storage facilities along the lower Mississippi handle more cargo by volume than any other port in the United States. Other key ports along the Gulf Coast still shut by the storm include Biloxi, Gulfport and Pascagoula, Miss., among the hardest-hit by the storm. Meanwhile, offshore-drilling contractors reported several semisubmersible rigs broke their moorings during the storm and were adrift in the Gulf, adding to flotsam of navigational hazards clogging the sea lanes off Louisiana and Mississippi. Among rigs adrift were the Deepwater Nautilus, belonging to Transocean Inc. and Offshore Drilling Inc.'s Ocean Voyager.