WASHINGTON - Legal advocacy groups sounded alarms on March 22 after US President Donald Trump threatened new actions against lawyers and law firms that bring immigration lawsuits and other cases against the government that he deems unethical.

In a memorandum to US Attorney General Pam Bondi late on March 21, Mr Trump said lawyers were helping to fuel “rampant fraud and meritless claims” in the immigration system, and directed the Justice Department to seek sanctions against attorneys for professional misconduct.

The order also took aim at law firms that sue the administration in what Mr Trump, a Republican, called “baseless partisan” lawsuits. He asked Ms Bondi to refer such firms to the White House to be stripped of security clearances, and for federal contracts they worked on to be terminated.

Mr Ben Wizner, a senior lawyer at the American Civil Liberties Union (ACLU), said the new directive sought to “chill and intimidate” lawyers who challenge the president’s agenda. Mr Trump has separately mounted attacks on law firms over their internal diversity policies and their ties to his political adversaries.

“Courts have been the only institution so far that have stood up to Trump’s onslaught,” Mr Wizner said. “Courts can’t play that role without lawyers bringing cases in front of them.”

The ACLU is involved in litigation against the administration over immigrant deportations, including the expulsion of alleged Venezuelan gang members.

The Trump administration has been hit with more than 100 lawsuits challenging White House actions on immigration, transgender rights and other issues since the start of the president’s second term. Legal advocacy groups, along with at least 12 major law firms, have brought many of the cases.

A White House spokesperson, Ms Taylor Rogers, said: “President Trump is delivering on his promise to ensure the judicial system is no longer weaponised against the American people.”

The Justice Department did not immediately respond to requests for comment on the memorandum, which directed Ms Bondi to assess lawyers and firms that brought cases against the government over the past eight years.

Law firm Keker, Van Nest & Peters, which is working with the ACLU in an immigrant rights case...