ANN ARBOR, Mich. -- Michigan is banning purses and all other bags from Michigan Stadium for security reasons, and the Pittsburgh Pirates are planning additional screening measures, too.

The University of Michigan said Wednesday it will require written permission from a medical professional before allowing any bags into the football stadium for Saturday's game against Indiana.

Recent arrests in Colorado and New York related to a terrorism probe touched off a flurry of national security bulletins. Michigan said in a statement that "adjusting security measures is the prudent thing to do."

School safety Deputy Chief Charlie Noffsinger said Michigan hasn't received information on any specific threats but acted after consulting with federal officials.

In Pittsburgh, the Pirates are tightening security because of the recent warnings and the G-20 summit Thursday and Friday at the downtown David L. Lawrence Convention Center, across the Allegheny River from PNC Park.

The Pirates play the Reds on Thursday afternoon and the Dodgers on Friday night.

"Even though we do not expect any issues during the G-20 summit, we have boosted the number of security personnel in and around the ballpark," Pirates spokesman Jim Trdinich said. "We will have additional screening with metal detecting wands at the gates for precautionary reasons."