Law enforcement is worried that terrorists may impersonate police officers, firefighters and EMTs to launch deadly attacks inside the U.S. just as Pope Francis visits the region this week.

A memo distributed by the Pennsylvania State Police's Criminal Intelligence Center to law enforcement warns that imposters pretending to be first responders could use false identification to gain access to secure areas, said Maria Finn, spokesperson for the Pennsylvania State Police. "The impersonators' main goals are to further their attack plan and do harm to unsuspecting citizens as well as members of the emergency services community," said the bulletin.

The document cited instances at home and abroad where suspects possessed police uniforms in a bid to carry out an attack. In March, U.S. authorities said derailed plans by Army National Guard soldier Hasan Edmonds, 22, and his cousin to kill dozens at a U.S. military installation in Illinois using his uniforms. In April, French authorities arrested ISIS sympathizer Sid Ahmed Ghlam, a 24-year-old Algerian national, and foiled his alleged plot to attack a church in Southern France. Ghlam was also in possession of police armbands.

Security during the papal visit will be at levels expected for the presidential State of the Union address, reported CNN. Efforts will be especially intense during Francis' stop in Philadelphia, which will host the largest public event on his tour. A 15-year-old Philadelphia boy inspried by ISIS was arrested in August for planning an attack on the pope.

The Pope left Rome and arrived in Cuba Saturday. He goes to Washington, D.C. on Tuesday, New York City on Thursday and then to Philadelphia for the World Meeting of Families on Saturday.

Here is his itinerary for the Philadelphia portion of his trip, according to the Vatican:

Saturday, Sept. 26 8:40 a.m. Departure from John F. Kennedy International Airport

9:30 a.m. Arrival at Atlantic Aviation, Philadelphia

10:30 a.m. Mass at Cathedral Basilica of Sts. Peter and Paul, Philadelphia

4:45 p.m. Visit to Independence Mall

7:30 p.m. Visit to the Festival of Families Benjamin Franklin Parkway Sunday, Sept. 27