President Donald Trump's crackdown on immigration has put a renewed focus on "sanctuary" cities. Here's what that means.

The U.S. Justice Department said on Thursday it was probing the release by an upstate New York sheriff's office of an immigrant living in the U.S. illegally, in what appears to be its first use of a new policy to target state and local agencies that do not comply with President Donald Trump's directives.

Syracuse Mayor Ben Walsh says the term "sanctuary city" can hold a lot of weight and is a term he tends to avoid.

The mayors of those cities are being called to testify before Congress. Fact check: $50 million for condoms in Gaza? Five big reasons to be skeptical Trump’s story is true

Four sanctuary cities are under federal investigation for their immigration policies, including Denver, Chicago, New York City and Boston.