PHOENIX (AP) — The U.S. Justice Department sued Sheriff Joe Arpaio on Thursday, saying the Arizona lawman refused for more than a year to turn over records in an investigation into allegations his department discriminates against Hispanics.

The lawsuit calls Arpaio and his office’s defiance ‘‘unprecedented,’’ and said the federal government has been trying since March 2009 to get officials to comply with its probe of alleged discrimination, unconstitutional searches and seizures, and jail policies that discriminate against people with limited English skills

Arpaio had been given until Aug. 17 to hand over documents the federal government first asked for 15 months ago.

Arpaio called the Justice Department actions harrassment at a news conference Thursday morning in downtown Phoenix. His office has said it won’t hand over additional documents because federal authorities haven’t said exactly what they were investigating.

‘‘They have hundreds of thousands of reports, hundreds of thousands,’’ Arpaio said. ‘‘They’re so broad, we’re trying to narrow it down. We’re trying to work with them.’’

The lawsuit is the latest action against Arizona by the federal government, which earlier sued the state to stop its strict new immigration law that requires police officers to question people about their immigration status if there is reason to suspect they are in the country illegally.

‘‘The actions of the sheriff’s office are unprecedented,’’ said Thomas Perez, assistant attorney general for the department’s civil rights division. ‘‘It is unfortunate that the department was forced to resort to litigation to gain access to public documents and facilities.’’

The lawsuit said the department is investigating police practices and jail policies but did not specify the documents sought in its dozens of requests. It was filed in U.S. District Court in Phoenix and names Arpaio, the Maricopa County Sheriff’s Office and the county.

Arizona’s new law — most of which a federal judge has put on hold — mirrors many of the policies Arpaio has put into place in the greater Phoenix area. Arpaio believes the inquiry is focused on his immigration sweeps, patrols where deputies flood an area of a city — in some cases heavily Latino areas — to seek out traffic violators and arrest other offenders.

Critics say his deputies pull people over for minor traffic infractions because of the color of their skin so they can ask them for their proof of citizenship.

Arpaio denies allegations of racial profiling, saying people are stopped if deputies have probable cause to believe they’ve committed crimes and that it’s only afterward that deputies find many of them are illegal immigrants.

The sheriff’s office has said half of the 1,032 people arrested in the sweeps have been illegal immigrants.

Last year, the federal government stripped Arpaio of his special power to enforce federal immigration law. The sheriff continued his sweeps through the enforcement of state immigration laws.

The department’s lawsuit said Arpaio’s office signed agreements promising to cooperate with civil-rights investigations and other reviews when it accepted federal law enforcement grants.

Last year, the nearly $113 million that the county government received from the federal government accounted for about 5 percent of the county’s $2 billion budget. The lawsuit listed $16.5 million of funding provided Arpaio’s office through several programs.

In a separate investigation, a federal grand jury in Phoenix is examining allegations that Arpaio has abused his powers with actions such as intimidating county workers by showing up at their homes at nights and on weekends.

A Hispanic activist said a federal judge might have to threaten jail time to get Arpaio to cooperate in the lawsuit filed Thursday.

Hispanics alleging racial profiling by Arpaio’s deputies in a lawsuit already pending in federal court have met with resistance in their own dcoument demands, said Lydia Guzman of the Phoenix-based civil rights group Somos America.

‘‘It’s going to take the hard hand of the judge to order some sanctions against the sheriff’s office,’’ Guzman said.