DALLAS -- Dallas joined a growing list of Texas cities on Wednesday challenging SB4, a sweeping and controversial immigration enforcement measure.

Mayor Mike Rawlings said the council has asked the city attorney to join San Antonio and Austin in the legal challenge to the so-called "sanctuary cities" bill.

"The bill is unconstitutional and would infringe upon the city’s ability to protect public safety," Rawlings said in a statement.

SB4, called the "show-me-your-papers-law," by critics allows law enforcement to ask about the legal status of any immigrant lawfully arrested or detained.

The bill also prevents cities from allowing it's police departments from adopting policies that forbid asking about legal status.

"It infringes on our police officers' ability to do their jobs," Rawlings told reporters late Wednesday.