Off-duty police officers are being told to leave their guns at home if they plan on attending an event for the pope this weekend, according to an internal memo posted by the police's union.

The letter says that everyone who attends any one of the planned events will need to be screened.

"Therefore, all members of the service who plan to attend a papal event while off-duty are hereby advised that firearms will not be permitted. Any member with a firearm will be excluded from the event."

Several law enforcement agencies are "involved in insuring a safe and secure visit" for all events, including His Holiness' procession through Central Park and his visit to St. Patrick's Cathedral, according to the memo. The visit, which coincides with the United Nations General Assembly, presents an unprecedented security challenge, officials have said.

The memo, however, didn't go over well with Patrick Lynch, president of the Patrolmen's Benevolent Association, the police union.

"The message ordering New York City Police Officers to leave their weapons at home if they are off-duty and attending a Papal event is dangerous," Lynch said in a statement. "Our officers are fully trained professionals who are on-duty around the clock and would represent additional response resources in the event of an emergency. Limiting their ability to intervene is foolish and flies in the face of common sense and public safety. It reduces the city's ability to protect his Holiness, it doesn't enhance it."