An immigration detention center in New Jersey is at the center of tensions between three congressional Democrats and the Trump administration after the arrest of Newark’s mayor outside the facility.

Ras Baraka, the Democratic mayor of Newark, New Jersey, was arrested on Friday while joining members of Congress at an Immigration and Customs Enforcement detention center, according to interim U.S. Attorney for the District of New Jersey Alina Habba.

Newark Mayor Ras Baraka was arrested at a new U.S. Immigration and Customs Enforcement facility in his city on Friday, escalating tensions between local officials and federal authorities.