WASHINGTON –– Ports and ships are operating under heightened security after the Coast Guard warned of a possible terrorist attack by either swimmers or divers. Cmdr. Jim McPherson, a spokesman for the Coast Guard, said Monday the warning was issued over the weekend after the agency received reports of a possible attack. The Bush administration warned last month of possible terrorist activity by scuba divers. The new warning went to local Coast Guard units, who then notified port authorities, marine patrols and the maritime industry, he said, and added that the Coast Guard offered specific actions that ports could do...