Attorney General Jeff Sessions said the "statement of interest" filed Friday in one suit over the issue advances President Donald Trump's goals of toughening immigration enforcement. | Chip Somodevilla/Getty Images

The Trump administration went to court Friday to defend a newly passed Texas law aimed at so-called sanctuary cities that decline to cooperate with federal immigration officials.

The Justice Department is siding with the state in a legal fight with local jurisdictions insisting that the new law is unconstitutional because it intrudes on areas governed by federal law and by seeking to commandeer local officials as federal agents.

Attorney General Jeff Sessions said the "statement of interest" filed Friday in one suit over the issue advances President Donald Trump's goals of toughening immigration enforcement.

"President Trump has made a commitment to keep America safe and to ensure cooperation with federal immigration laws. Texas has admirably followed his lead by mandating state-wide cooperation with federal immigration laws that require the removal of illegal aliens who have committed crimes," Sessions said in a statement. “The Department of Justice fully supports Texas’ effort and is participating in this lawsuit because of the strong federal interest in facilitating the state and local cooperation that is critical in enforcing our nation’s immigration laws.”

The first lawsuit against the law was filed last month by the small border city of El Cenizo. Several other localities, including Texas' four largest cities — Houston, Dallas, San Antonio and Austin — are backing the El Cenizo challenge or pursuing other suits,

U.S. District Court Judge Orlando Garcia, an appointee of President Bill Clinton, has scheduled a hearing for Monday on the plaintiffs' request for a preliminary injunction against the measure. The law is not set to kick in until September 1.

Much of the dispute revolves around how localities deal with requests immigration authorities make to detain individuals in the custody of local police or sheriffs. The new law requires local governments to honor such requests in most circumstances, although existing federal law imposes no such requirement.

"Parties may disagree with the state legislature’s policy determinations in enacting SB 4, but nothing in federal immigration law precludes a state from directing law enforcement officers in the state to cooperate with the federal government, rather than merely permitting them to do so on an ad hoc basis," the Justice Department filing says.

Justice Department lawyers also say local authorities with a policy of enforcing immigration "detainers" are not running afoul of the Fourth Amendment's guarantee against unreasonable detention of individuals.

"Compliance with such detainers does not violate the Fourth Amendment. Speculation that a detainer request might be issued in contravention of federal policies, and might be constitutionally improper, provides no basis for the facial invalidation of a state law that provides for cooperation with a system of warrants authorized by Congress," the Justice Department wrote.

Justice Department lawyers say they also plan to show up at the court hearing on Monday and will seek to argue the federal government's position in favor of the Texas law.