Commuters are being asked to keep their eyes open and report suspicious activity, especially as they use public transportation.

On Friday morning, officials unveiled a newly wrapped Metro Transit bus and light-rail train that will be "traveling billboards" for the message, "If you see something, say something."

The campaign is the joint work of Metro Transit and the state and federal departments of Homeland Security.

Officials said they want to encourage people to be aware of anything out of the ordinary in their regular commutes: unattended backpacks, people and cars parked out of place.

"No matter how hard we try, we can't be everywhere," said A.J. Olson, Metro Transit police chief. "We believe this message will resonate with our passengers."

The campaign has proved effective since it was launched by the New York Transit Authority and U.S. Department of Homeland Security in 2010.

In the Twin Cities, the slogan will be carried for several months on the bus and train and at transit stations and kiosks.

ASHA ANCHAN