The Transportation Security Administration has quietly yet vastly expanded its reach to sporting events, music festivals, rodeos, highway weigh stations and train terminals, according to the Star-Tribune.

TSA and local law enforcement officials say the Visible Intermodal Prevention and Response squads – dressed in bulletproof bets and performing random security sweeps to prevent terrorist attacks at transportation hubs across the U.S. – are a critical component of the nation’s counterterrorism efforts. Some members of Congress, auditors at the Department of Homeland Security and civil liberties groups are sounding alarms, however. The teams are also raising concerns among passengers who call the sweeps unnecessary and intrusive, the article reports.