The typically hushed corridors of the Russell Senate Building echoed with noise Monday as protesters, upset by the Senate Republicans’ health care bill, descended on lawmakers’ offices to let their displeasure be known ― part of several such demonstrations around the U.S. Capitol.

An initial crowd estimated at around 100 protesters split into smaller groups once inside the building, with each subgroup seeking out the offices of specific senators, some of whom are positioned to cast critical swing votes on the legislation.

Capitol Police said in a statement they responded to 13 locations in Senate and House office buildings and as of late Monday afternoon had made 80 arrests. The officers “warned the demonstrators to cease and desist with their unlawful demonstration activities,” according to the statement, and those who did not were charged under a law prohibiting “crowding, obstructing, or incommoding.”

A group of around 20 protesters visited the office of Sen. Jeff Flake (R-Ariz.) in the Russell building, where they proceeded to enter and chant against what their signs termed “Trumpcare.” Ten later sat on the floor outside Flake’s office, where they chanted “Kill the bill” and “Flake, where are you?”