U.S. embassies and other government sites around the world were on alert Monday and the State Department issued a travel alert for Americans abroad in case of retaliation following the killing of al Qaeda leader Osama bin Laden.
The State Department said U.S. government facilities worldwide "remain at a heightened state of alert" on news of the raid in Pakistan that killed the leader of the September 11 terror attacks.
"These facilities may temporarily close or periodically suspend public services to assess their security posture," the department said in a statement issued late Sunday.
Given the uncertainty and volatility of the current situation, U.S. citizens in areas where recent events could cause anti-American violence are strongly urged to limit their travel outside of their homes and hotels and avoid mass gatherings and demonstrations," the department said.
UPDATE 9:30 a.m. May 2, 2011
Added security was evident across the New York City area the morning after the raid in Pakistan.
"In light of the events that are unfolding, the port authority has directed its police to increase its presence at all port authority facilities, including the World Trade Center site, and to coordinate with local, state and federal law enforcement as required," said Chris Ward, executive director of the Port Authority of New York and New Jersey. "This response is not based on a current threat, but out of an abundance of caution until we have the chance to learn more. In the meantime, all port authority facilities remain fully operational and at normal service levels."