Just hours after President Donald Trump signed an executive order to allow for new “extreme vetting” measures of immigrants, the Council on American-Islamic Relations, a civil rights advocacy group, announced that they plan to file a lawsuit.

“There is no evidence that refugees – the most thoroughly vetted of all people entering our nation – are a threat to national security,” said CAIR National Litigation Director Lena F. Masri said in a statement to LawNewz.com.

Trump’s order suspends the immigration of all people from countries with ties to terror including Syria, Yemen, Sudan, Somalia, Iraq, Iran and Libya for 90 days. The order also prohibits Syrian refugees from coming into the U.S. for an undefined period.

“We are not admitting into the country the very threats our soldiers are fighting overseas,” Trump said during General James Mattis swearing ceremony.

On Monday, CAIR said they will hold a news conference in Washington, D.C., to announce the filing of a federal lawsuit on behalf of more than 20 individuals challenging the so-called “Muslim ban.”

“This is an order that is based on bigotry, not reality,” Masari said.  The group says they plan to wage a constitutional challenge to the executive order. The Trump order does not have language the bans Muslims explicitly. However, the order does say when the ban is lifted that federal agencies are instructed to prioritize refugee claims made by individuals “on the basis of religious based discrimination, provided that the religion of the individual is a minority religion in the individual’s country of nationality.” This could exclude many Muslims.

The American Civil Liberties Union has said that a Muslim ban would possibly violate the Establishment Clause of the First Amendment by disapproving of one religion and implicitly preferring others.

“‘Extreme vetting’ is just a euphemism for discriminating against Muslims. Identifying specific countries with Muslim majorities and carving out exceptions for minority religions flies in the face of the constitutional principle that bans the government from either favoring or discriminating against particular religions. Any effort to discriminate against Muslims and favor other religions runs afoul of the First Amendment,” American Civil Liberties Union Executive Director Anthony D. Romero said in a statement.

On the other hand, the Supreme Court has given the federal government and the presidency wide authority to set immigration policy, and other experts say this move could skirt the legal line.