The city of San Antonio and three nonprofits filed a federal suit on Thursday against the state’s anti-sanctuary cities law, calling it unconstitutional.

The suit was brought by the Mexican American Legal Defense and Educational Fund, or MALDEF, against what they called the toughest immigration law in the nation. The law, also formerly known as Senate Bill 4, is set to go into effect Sept. 1.

"The constitutional violations in this law are substantial and multiple, and the lawsuits challenging SB4 should prevent its threatened unleashing of arbitrary and inconsistent law enforcement practices," said Tom Saenz, MALDEF's president and general counsel.

The city of Austin is expected to intervene on the new law Friday morning, said Austin City Councilman Greg Casar in a MALDEF news conference.

San Antonio and the nonprofits now join others who have sued separately, including the small city of El Cenizo, the Maverick County sheriff, El Paso County and the League of United Latin American Citizens, or LULAC. Eventually, the suits are expected to be consolidated.

The groups seek a federal injunction to halt implementation of the new law, which has already increased fear of being deported in many immigrant communities across the state. The latest suit was filed in San Antonio in federal court.

The suit argues that the law created by SB4 is unconstitutional based on the Supremacy clause within the Constitution, which says federal law preempts state law. The suit also cites the First, Fourth and Fourteenth amendments.

“The impact of SB4 will be devastating to Texas local governments and institutions of higher education because it hijacks their authority to enact policies that best fit their localities unique needs,” the suit reads.

“Undoubtedly,” other municipalities will file suits, Saenz said in the conference call. But when asked about the cities of Dallas and Houston, Saenz declined comment, citing client confidentiality.

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The three nonprofits involved in the new suit are Workers Defense Project, Texas Association of Chicanos in Higher Education and La Union de Pueblo Entero. Jose Garza, the executive director of the Workers Defense Project, said his nonprofit, which has offices in Dallas, will continue to advocate with for Dallas city officials to file a suit.

The matter is expected to be taken up by the Dallas city council this month, Dallas City Attorney Larry Casto has said.

The law bans cities, counties and universities from prohibiting peace officers from asking about immigration status or enforcing immigration law. It calls for local law enforcement to “comply” with “immigration detainer requests” from Immigration and Customs Enforcement, or ICE.

Local governments that don’t comply can be fined from $1,000 a day escalating to $25,500 for subsequent violations. The bill exempts schools, and when dealing with victims or witnesses to crime, it limits immigration questions.

Andy Segovia, San Antonio’s city attorney, and Saenz said one of the harshest provisions in the law was aimed at public officials who don’t comply. That, Segovia said, “really undermines the ability of public officials to do what they are elected to do.”

Supporters of the bill say its reach is more limited than many Latino organizations, immigrant advocates and their supporters believe. They argue that it only permits local law enforcement to stop people already in the U.S. without papers from committing crimes. Abbott defended the law by saying it had “already been tested” at the U.S. Supreme Court in an Arizona case in 2012.

Last month in Austin, Abbott tried to tamp down fears of racial profiling by emphasizing his wife Cecilia is Mexican-American. "As the husband of the first Hispanic first lady in the state of Texas, I want to make sure that neither she nor her family is gonna be stopped or detained inappropriately," Abbott said.