Three major civil-rights organizations on Tuesday filed a federal lawsuit challenging the Trump administration’s plans to institute harsh new restrictions on access to the U.S. asylum system.

The suit, filed by the American Civil Liberties Union, the Southern Poverty Law Center and the Center for Constitutional Rights, alleges that a proposed rule change announced on Monday by the Departments of Justice and Homeland Security amounts to “an unlawful effort to significantly undermine, if not virtually repeal, the U.S. asylum systemat the southern border, and cruelly closes our doors to refugees fleeing persecution, forcing them to return to harm.” 

The proposed rules would severely restrict access to the asylum system, forbidding nearly every migrant from pursuing an asylum claim in the United States if they did not first seek asylum protections in the country or countries through which they traveled on their way to the U.S. border. “This is the Trump administration’s most extreme run at an asylum ban yet,” said Lee Gelernt, deputy director of the American Civil Liberties Union’s Immigrants’ Rights Project, in a release announcing the lawsuit. “It clearly violates domestic and international law, and cannot stand.”