Via Police Magazine:

On the day following the killing of 9/11 mastermind Osama bin Laden at a northern Pakistan compound by a U.S. strike team, law enforcement agencies urged the public to watch out for and report any suspicious activity.

Following the killing of bin Laden, Homeland Security briefings urged law enforcement agencies to remain alert for any potential retaliatory strikes. Law enforcement leaders who spoke publicly made it clear they weren't aware of any specific threats.

"For years this county has been well-prepared to deal with any emergency," Los Angeles Sheriff Lee Baca said outside Los Angeles County's emergency operations center. Cooperation between local, state and federal law enforcement has improved since 9/11, Baca said, and critical points such as mass transit, ports, stadiums and airports have been further secured.

Transportation agencies in New York and Washington, D.C., both announced they have put in place additional precautionary measures.

"Metro Transit Police and our jurisdictional law enforcement partners are increasing security of the Metro system as a precautionary measure related to the death of bin Laden," according to a Washington Metropolitan Area Transit Authority statement released Monday. "Please know that this increased security is not related to any specific threat, rather it is out of an abundance of caution."

Additionally, the U.S. Capitol Police announced additional security around federal legislative facilities.

"While we continue to monitor and share intelligence with our law enforcement partners, USCP has implemented enhanced security measures in and around the Congressional Office Buildings," Capitol Police spokeswoman Sgt. Kimberly Schneider said in a statement.

While many agencies further secured physical sites, others such as the Michigan State Police issued a statement asking citizens to step up their efforts to observe and report.

"The public plays a critical role in partnering with public safety officials to prevent, respond to, and recover from all potential threats and acts of violence," according to the statement. "Citizens are reminded to be on the lookout for the seven signs of terrorism-surveillance, elicitation, tests of security, acquiring supplies, suspicious persons out of place, dry run/trial run and deploying assets.