The Supreme Court has struck down key provisions of Arizona's laws on immigration. 

According to the Associated Press, the court said Monday that one part of the law requiring police to check the status of someone they suspect is not in the United States legally could go forward. Even there, though, the justices said the provision could be subject to additional legal challenges.

More from the AP:

The justices said the federal government has the ultimate authority to decide who will be held on immigration charges and deported.

While police cans stop people they suspect are illegal immigrants, the justices said the police have limited authority. They must check with federal immigration agents before deciding to hold the suspects.

The justices also blocked parts of the Arizona’s SB 1070 that would have made it state crime for illegal immigrants to carry documents or to seek work.

The court’s decision appears to give states such as Arizona a quite limited role in enforcing the laws against illegal immigrants.

Their police can notify federal agents if they have a suspect in custody, but they cannot keep them in a county jail on state charges.