US says security at 'heightened state of vigilance'

WASHINGTON - US homeland security officials are at a "heightened state of vigilance" for possible retaliatory attacks in the wake of American forces killing al Qaida leader Osama bin Laden, US Homeland Security Secretary Janet Napolitano said on Monday.
The Homeland Security Department has no plans to issue a specific advisory about credible or imminent threats at this time, she said in a statement.
"Our security posture, which always includes a number of measures both seen and unseen, will continue to respond appropriately to protect the American people from an evolving threat picture both in the coming days and beyond," Napolitano said.
The US Homeland Security Department scrapped the color-coded warning system last month and said it would instead issue alerts only when credible or specific threats emerged.