Federal public service workers are facing heightened security at some of their Ottawa buildings and told to be vigilant after an incident Friday at the headquarters of Canada's electronic spy agency.

Ottawa Police confirm uniformed officers are on paid duty at the Communications Security Establishment building on Ogilvie Road as of Friday.

Police say they are investigating an incident Friday at the new headquarters for the electronic spy agency, but declined to provide details about the incident.

A memo, widely distributed throughout the public service, is asking workers to watch out for any suspicious individuals or packages.

The memo said "in the last week, a few individuals have been seen exhibiting suspicious behaviour around federal facilities."

Watch for people entering buildings without access

Employees are asked to watch out for people trying to enter buildings without access, or for briefcases left behind.

Larry Rouseau, the National Capital Region representative for the Public Service Alliance of Canada, said since the shooting on Parliament Hill in October 2014 there has been more attention paid to security concerns at federal buildings.

A statement from the federal government's Privy Council Office confirmed the email reminding employees of security best practices was sent, but declined to comment on the reason for the email.