PHOENIX (AP) — A federal appeals court is refusing to lift a stay blocking major parts of a tough Arizona law targeting illegal immigrants from taking effect.

The 9th U.S. Circuit Court of Appeals on Monday turned down an appeal filed by Gov. Jan Brewer. The governor asked them to lift an injunction imposed by a federal judge in Phoenix the day before the law was to take effect on July 29, 2010.

The U.S Justice Department sued to block the law. It argued it violates the constitution because enforcing immigration law is a federal issue.

Brewer’s lawyers said the federal government hasn’t effectively enforced immigration law and that the state law will assist federal authorities.

The law would require police to check immigration status when enforcing other laws, among other provisions.