Story highlights Among the requirements: Letting federal authorities access detainees in jails

Sanctuary cities have been a key focus of the Trump administration and Republicans in Washington

Washington (CNN) The Trump administration opened up a new salvo against sanctuary cities on Tuesday -- moving to make immigration enforcement a pre-condition for receiving key law enforcement grants.

Attorney General Jeff Sessions announced Tuesday evening that applicants for Edward Byrne Memorial Justice Assistance Grants will be required to certify that they'll cooperate with federal immigration enforcement more extensively than in the past, a move that is likely to generate court challenges quickly from advocates and state and local jurisdictions who have opposed President Donald Trump's efforts.

Among the requirements: Letting federal authorities access detainees in jails to inquire about immigration status and giving the federal government 48 hours' notice before any inmate they're interested in is released.

The term sanctuary city loosely refers to jurisdictions that in some way do not cooperate with federal immigration enforcement. Localities have a variety of justifications for doing so, from protecting undocumented immigrants to preserving law enforcement's ability to gain the trust and cooperation of communities. Some jurisdictions have also been barred by the courts from complying with certain federal requests.

Trump himself railed against sanctuary cities during a rally in Youngstown, Ohio, on Tuesday. He drew out a long and graphic description of violent gang members torturing and killing young women.

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