Trump's executive order sought to dismantle asylum at the southern border. Lawyers say it has been illegally extended to migrants inside the country.

The lawsuit, presented in the U.S. District Court for the District of Columbia, alleges Trump's effort to unilaterally ban access to asylum is "unlawful as it is unprecedented" because it overrides Congress' authority. The suit is joined by three immigrant rights groups.

The ACLU and other rights groups filed suit against it on behalf of legal service providers at the border — including the Phoenix-based Florence Immigrant and Refugee Rights Project.