Updated June 7 at 6:00 p.m. to include include Mayor Mike Rawlings' comments.

Dallas is joining some other Texas cities, including Austin and San Antonio, in taking on the state's so-called "sanctuary city" law.

Mayor Mike Rawlings made the announcement Wednesday afternoon, calling SB4 "unconstitutional" and a law that "greatly infringes on the city's ability to protect" the public. According to Rawlings, the city attorney has "serious constitutional concerns" with the new measure, which goes into effect Sept. 1.

Rawlings said after Wednesday's council meeting that he had already spoken with Austin Mayor Steve Adler and San Antonio Mayor Ivy Taylor about potential litigation.

"I told them both this was a serious issue," Rawlings said.

A San Antonio federal district court announced Wednesday it would consolidate the lawsuits filed by all of the cities against the bill and designate the city of El Cenizo as the lead plaintiff. A hearing in that case is set for June 26.

Critics call SB4 the "show-me-your-papers law," because it allows law enforcement to question the immigration status of anyone who has been lawfully arrested and detained. In addition, it could punish cities, counties and universities who do not enforce the law.

Here's @Mike_Rawlings' brief statement concerning Dallas' decision to join Austin and San Antonio's legal challenge to #SB4 pic.twitter.com/vtPJniCtQO — Robert Wilonsky (@RobertWilonsky) June 7, 2017

And police chiefs, county sheriffs and constables who do not enforce the law could face criminal charges, and local jurisdictions could be fined up to $25,000 per violation per day.

Gov. Greg Abbott and other supporters of SB4 say it would protect Texans from crimes committed by those who are in the country illegally.

Dallas makes its decision

The Dallas city code allows the city attorney to initiate litigation without the council's approval. Rawlings made his announcement moments after the City Council met with City Attorney Larry Casto behind closed doors.

Rawlings said he wanted to make sure the council was aligned before Dallas joined the fray. He said Wednesday that a majority of the council agreed with Casto's recommendation to take on the state.

"We are not a sanctuary city," he said. "We live by the national laws, and now the question is who's boss in all this. And this is an unfunded mandate. They're telling us how our police officers should spend their time and not giving us any money to do that."

Council member Philip Kingston said last month, during an SB4 protest in Austin, that Dallas would eventually join the fight against the legislation.

The official decision by Dallas to do just that followed a demonstration by about 60 protesters at City Hall Wednesday morning aimed at pressuring city leaders into challenging the controversial bill, which was signed by Gov. Greg Abbott last month.

Members of the Workers Defense Project, Texas Organizing Project and other local activists were among the protesters. Rawlings attended the rally and told the group the City Council would discuss the issue later during executive session.

Rawlings said then that he is concerned about how the law would affect his and other council members' roles in the community.

"My job, the job of the pro tem and the job of the council is to keep all citizens safe," the mayor said. "We want to have a safe environment so they can get married and do the things they have to do."

Rawlings said the law asks too much of police by making them enforce federal immigration laws in addition to focusing on "safety first."

"Time and time again, police chiefs and police associations across the state have said that SB4 is not a safe bill," he said.

After a few minutes of chanting, @Mike_Rawlings spoke, said Dallas City Council planned to discuss #SB4 during exec session. pic.twitter.com/ipRGP8Q16R — Elvia Limón (@elvialimon) June 7, 2017

'Stop this hateful law'

Carla Hernandez said she decided to join the protesters because she did not feel safe. Hernandez, 37, said she was afraid she would be separated from her children.

"I've had panic attacks when I've had to pick up my children," Hernandez said. "We want the mayor to give us support to join the lawsuit. I have confidence that there's more support than hate."

During the council meeting following the protest, several opponents of the law spoke to the council and pleaded with them not to support the law.

{"type":"video","title":"Dallas News Video","author_name":"Dallas News","_id":"ptZjFpYjE6CFNEm7zlEaB9srt9ccL7mS","provider_name":"Ooyala","html":"

","raw":"{\"type\":\"video\",\"title\":\"Dallas News Video\",\"author_name\":\"Dallas News\",\"_id\":\"ptZjFpYjE6CFNEm7zlEaB9srt9ccL7mS\",\"provider_name\":\"Ooyala\",\"html\":\"\\u003Cdiv class=\\\"oo-vid-container\\\" data-oo-content-id=\\\"ptZjFpYjE6CFNEm7zlEaB9srt9ccL7mS\\\"\\u003E\\u003C\\/div\\u003E\\u003Cscript defer src=\\\"https:\\/\\/www.dallasnews.com\\/resources\\/motif\\/dist\\/js\\/ooyala.js\\\"\\u003E\\u003C\\/script\\u003E\"}","providerType":"ooyala","providerLink":"https://www.dallasnews.com/oembed","embedType":"video"}

Manuela Castro said she knew of people who have already been detained and deported and said the measure would eventually hurt Dallas businesses that depend on immigrant labor.

"The law hasn't gone into effect and there are already people who have been detained and police officers who are asking for their papers," she said. "Please help us stop this hateful law."

Solia Chaver of Lancaster told the city council she worries about how the sanctuary cities law will affect immigrants protected under temporary visas and permits, such as the Defered Action for Childhood Arrivals for unauthorized immigrants who came to the U.S. as children and Temporary Protected Status for immigrants who are unable to return safely to their country of origin.

"We have a lot of students who are currently protected by DACA, and people like me, who are protected under TPS," she said. "If the law goes into effect, they will only give us three months to renew our paperwork. So what's going to happen to us? Are we also going to be deported?"

Law enforcement weighs in

Two members of the law enforcement community -- Executive Chief Deputy Jesse Flores and Chief Deputy Jesse Herrera from the Dallas County Sheriff's Department --also addressed the Dallas council about SB4.

Flores said that even though the sheriff's department has always cooperated with the U.S. Immigration and Customs Enforcement agency when handling criminals who are unauthorized immigrants, he believed the law could lead to fewer reported crimes by community members who will be afraid to interact with law enforcement.

"If members of the community are afraid to come forward and report crimes due to fear of deportation, then those crimes will not be reported or investigated," Flores said. "Senate Bill 4 will also affect vulnerable people at risk, because women and children are least likely to come forward if they are undocumented. We believe our community is safer when they report crimes without fear of deportation."

In addition to those concerns, there was evidence the bill is already beginning to impact business in the the state.

The American Immigration Lawyers Association, a 15,000-member assocation of attorneys and law professors announced Wednesday that it would relocate its 2018 convention out of Grapevine in response to the passing of SB4. About 3,000 people were expected to attend the three-day event.

Staff Writer Tristan Hallman contributed to this report.