By David Spunt and Pat Loeb

PHILADELPHIA (CBS) — The U.S. Justice Department has sent a letter to officials in Philadelphia, and six other cities, ordering them to verify that they are in compliance with a federal immigration law. If not, those cities risk losing federal grant money.

U.S. Attorney General Jeff Sessions warned that the Trump administration will punish communities that refuse to cooperate with efforts to find and deport immigrants in the country illegally.

The letter addressed to Mayor Jim Kenney demands a response by June 30. The letter is asking Kenney to verify that Philadelphia allows local law enforcement to share immigration case information with federal immigration authorities. If the city does not comply it could lose a $1.7 million annual grant for local law enforcement efforts.

“We have been aware of the requirement to certify since 2016, and we believe there is nothing in our current policy that prohibits us from certifying,” said a spokesperson for Kenney.

Homeland Security Secretary John Kelly threatened additional consequences for local police that don’t deliver people in custody, saying the alternative is immigration agents searching neighborhoods.

“Ideally the best place for us to pick up these illegal criminals is in jails and prisons,” Kelly said at a news conference with Sessions in San Diego, next to a border fence topped with razor wire. “If they don’t do that, then we have to go into neighborhoods. We have to go into courthouses. We have to go wherever we can find them and apprehend them.”

Letters were also sent to New York, Chicago, Miami, New Orleans, Las Vegas, Milwaukee, and the California Department of Corrections.