Chicago, Nov 15 (AP) Authorities arrested 21 protesters Friday and said four officers were injured outside a Chicago-area federal immigration facility that activists say functions as a de facto detention center and is plagued by inhumane conditions.

The Cook County Sheriff's Office said the arrests were made by midday, and that it was working on verifying identities and potential charges.

The office said in a later statement that four officers were injured while trying to redirect protesters off a roadway and back behind a barrier. Two Broadview police officers and one Cook County Sheriff's Police officer were taken to a hospital. The Sheriff's Police officer sustained a lower leg injury and was treated and released. The statement did not give details on the Broadview officers' injuries or conditions. But it also said an Illinois state trooper was treated at the scene.

Just moments before the clash, demonstrators were singing and chanting. Around 10 a.m., a large group, knowing they were going to be arrested, allegedly crossed the protest barrier and attempted to walk up toward the U.S. Immigration and Customs Enforcement facility.

Some protesters carried signs reading, “God's Love Knows No Borders” and “God Demands Freedom.” Some of them prayed. The crowd numbered about 300 before it began to disperse.

The facility in Broadview, Illinois, has been the site of frequent protests, particularly on Fridays, against a federal immigration crackdown dubbed “Operation Midway Blitz.” It has led to more than 3,200 arrests in the Chicago metropolitan area since September of people suspecting of violating immigration laws .

The aggressive tactics used by agents from Customs and Border Protection and U.S. Immigration and Customs Enforcement have repeatedly come under fire through legal challenges as well as street protests. (AP) NB NB

Immigration enforcement tactics spur protest and clashes, leading to arrests and reported officer injuries outside a detention facility. Clashes outside a federal immigration detention facility occurred when demonstrators crossed barriers and approached the site, prompting law enforcement to redirect the crowd; this produced multiple arrests and injuries to officers. The facility is the target of recurring protests alleging inhumane conditions and opposition to a federal enforcement initiative called Operation Midway Blitz, and the protests form part of broader legal and public challenges to aggressive immigration enforcement tactics.