By Geneva Sands, Sonnet Swire and Christina Carrega, CNN

Authorities in northern Virginia on Friday announced an increased police presence amid warnings of a possible terrorist plot.

Authorities are determining the validity of the threat, according to a police source. As a precaution, federal and local law enforcement agencies are investigating and acting to protect potential targets, the source said.

The FBI and the Department of Homeland Security have notified state and local law enforcement officials in Maryland, Washington, DC and Virginia of a possible terrorist plot in the region in the coming days, according to the source.

In Fairfax County, Virginia, adjacent to Washington, police received reports of “potential public safety impacts on shopping malls and shopping centers in the area,” Chief Kevin Davis said in a statement. press briefing on Friday.

Police patrols will be stepped up in major thoroughfares, transit hubs, malls and malls in Fairfax County, Davis said. He also encouraged the public to be vigilant and to report any suspicious activity.

Davis declined to provide details of the threat, but called it a “regional issue.” To his knowledge, no one has been identified in connection with the threat, Davis said.

“Because we have received information that has public safety value, it is just our responsibility to have a greater presence, to be more aware and to ask the community to have their eyes and ears opened. for suspicious activity, ”he said.

The nearby Loudoun County Sheriff’s Office was aware of information about potential threats to malls and shopping malls this weekend in the Washington area, the office said in a press release on Friday.

The agency also said it was increasing patrols in high-visibility locations as it worked to corroborate the information with regional partners.

“This information is limited and there is nothing specific to Loudoun County,” the statement said.

FBI Washington Field Office spokeswoman Carly Kennedy declined to comment except that “the FBI takes all potential threats to public safety seriously and we are taking all appropriate steps to determine the credibility of any information. that we receive “.

The warnings come as US officials have raised concerns about domestic and foreign terrorist threats. At an event hosted by the Intelligence and National Security Alliance on Thursday, Homeland Security Intelligence Chief John Cohen said the situation in the United States was more “volatile, dynamic and complex.” than at any time in recent memory.

“We face an evolving foreign terrorist threat environment as conditions in Afghanistan, Yemen and other countries that are known areas of terrorist activity evolve. We face a threat sustained by violent extremists and national terrorists, “he said.

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