Officials with the City of Austin have announced they will officially file a challenge to the so-called "sanctuary cities" bill, SB 4, in federal court "for violations of the U.S. Constitution" Friday morning, according to a press release from Austin City Council member Greg Casar.

Meanwhile, the City of San Antonio has announced it is filing a challenge to the law Thursday night.

SB 4, which was signed into law by Gov. Greg Abbott on Facebook live, has been one of the most controversial topics during the 85th Legislative session, with various people protesting and giving emotional testimony against the bill.

Now, law enforcement agencies across the state are required to honor U.S. Immigration and Customs enforcement detainers. They're requests to hold someone in jail while their immigration status is checked out.