Washington - US Muslim leaders filed suit against President Donald Trump on Monday over an immigration order that they said was a "fear-mongering" attempt at keeping members of their religion out of the country.Nihad Awad, executive director of the Council on American-Islamic Relations, joined 26 others as plaintiffs in the lawsuit alleging that Trump's temporary ban on immigrants from seven Muslim-majority countries was in fact a "Muslim exclusion order" that violates the US constitution's religious freedom protections."Donald Trump's executive order is not based on national security, it is based on fear-mongering," Awad said on Monday."This is not a Muslim ban, it is a Muslim exclusion order."Violation of the constitution Besides excluding Muslim refugees and immigrants from abroad, the suit alleges Trump's executive order will force out US-resident Muslims from those seven countries "by denying them the ability to renew their lawful status or receive immigration benefits... based solely on their religious beliefs."That will lead to "the mass expulsion" of both immigrant and non-immigrant Muslims, the suit, filed in the district court in Alexandria, Virginia, alleged.Plaintiffs in the lawsuit include several CAIR officials, among them prominent Muslim-American lawyers and activists.They also include unnamed plaintiffs described as legal residents and visitors to the country who would, if they left temporarily, would not be able to return under Trump's order.The suit said the order, announced on Saturday, reflected anti-Muslim sentiments that Trump expressed during the presidential campaign."The Muslim Exclusion Order is the as-promised outcome of Defendant Trump's hateful, year-long campaign which was fueled, in significant part, by a desire to stigmatise Islam and Muslims," it said.Lawyers said the order violates the US Constitution's protections of religious freedoms and the "establishment clause," which bans the government from making laws that favour or discriminate against specific religions.