The federal government filed a lawsuit Monday seeking to stop implementation of South Carolina's tough new immigration law, arguing that the legislation that requires law officers to check suspects' immigration status is unconstitutional.

Federal officials and state officials had met to discuss the issue a week ago.

The government wants a judge to stop enforcement of the legislation, which requires that officers call federal immigration officials if they suspect someone is in the country illegally following a stop for something else, U.S. Attorney Bill Nettles told The Associated Press.

"The Department of Justice has many important tasks," Nettles said. "Two of those important tasks are the defense of the constitution and ensuring equality is afforded to all."

The lawsuit filed in federal court names Gov. Nikki Haley as a defendant. A spokesman for the Republican, the daughter of immigrants from India, said the state was forced to pass its own law because there is no strong federal immigration law.

"If the feds were doing their job, we wouldn't have had to address illegal immigration reform at the state level," Rob Godfrey said. "But, until they do, we're going to keep fighting in South Carolina to be able to enforce our laws."

A spokesman for state Attorney General Alan Wilson, who will act as Haley's attorney, said he had not seen the complaint.

South Carolina's law, which takes effect Jan. 1, also mandates that all businesses check their new hires' legal status through a federal online system. Businesses that knowingly violate the law could have their operating licenses revoked.

The law says all law enforcement officers are required to call federal immigration officials if they suspect someone is in the country illegally. The question must follow an arrest or traffic stop for something else. The measure bars officers from holding someone solely on that suspicion. Opponents railed against the measure as encouraging racial profiling.

The law also makes it a felony for someone to make fake photo IDs for illegal residents and creates a new law enforcement unit within the Department of Public Safety to enforce state immigration laws. It also makes it a felony for illegal immigrants to allow themselves to be transported.

Nettles said the law is unconstitutional and violates people's right to due process.

The U.S. Justice Department has been reviewing immigration-related laws passed by several states and is challenging similar laws in Arizona and Alabama. Last week, Nettles met with Wilson on the issue, but no details of that meeting were released.

Assistant attorney general Tony West said Monday the agency continues to review similar laws in Utah, Indiana and Georgia. He quoted Haley saying South Carolina's law would cause illegal immigrants to move elsewhere.

"Pushing undocumented individuals out of one state and into another is simply not a solution to our immigration challenges," West said. "It ultimately creates more problems than it solves."

Justice department officials said South Carolina's law, like Alabama's and Arizona's, diverts federal resources from high-priority targets, such as terrorism, drug smuggling and gang activity. They contend the laws will result in the harassment and detention of foreign visitors and legal immigrants, as well as U.S. citizens, who can't immediately prove their legal status.

A deputy assistant attorney general said the agency sent a letter to Alabama schools reminding them that children can't be denied enrollment. Unlike the laws in other states, Alabama's required schools to check students' immigration status. That provision, which has been temporarily blocked, would allow the Supreme Court to reconsider a decision that said a kindergarten to high school education must be provided to illegal immigrants.

The Justice Department has set up a hotline and email address for complaints regarding Alabama's law, and officials said they're coordinating with colleagues in other federal agencies -- including the labor, agriculture, education, and health agencies -- to ensure federal money's not being used to discriminate.

In a news release, Department of Homeland Security Secretary Janet Napolitano said South Carolina's law "diverts critical law enforcement resources from the most serious threats to public safety and undermines the vital trust between local jurisdictions and the communities they serve, while failing to address the underlying problem: the need for comprehensive immigration reform at the federal level."

The American Civil Liberties Union, which has challenged the similar laws in other states, several weeks ago sued to block the South Carolina law from taking effect in January.

"It definitely puts a spotlight on the issue and heightens our arguments," Andre Segura, an attorney with the ACLU's immigrants' rights project, said Monday.