CHICAGO (CBS) — As concerns about security grow in the run-up to the NATO summit, it’s becoming difficult to separate myth from reality.

Are there plans in place for a mass evacuation of downtown in the event of riots on May 20-21? A Red Cross memo out of Milwaukee indicates that there is.

Officials there have been asked to make plans to assist residents in the event of a mass exodus.

Chicago officials say the plan didn’t come from them. The U.S. Secret Service isn’t talking.

There also are reports that a heavily armed security team will start making a very public appearance around federal buildings in the Loop this week. Officials with the Chicago NATO host committee were completely in the dark. They had no reports of any such plans.

A source told CBS 2 that security forces in full battle gear would not be seen this week.