India, Sept. 15 -- A broad coalition of 22 US states and the District of Columbia launched a formidable legal challenge on Monday against the administration of US President Donald Trump, seeking to block a controversial expansion of the federal "public charge" immigration rule.

The measure links lawful permanent residency to the use of domestic assistance programmes. Filed in federal court, the lawsuit targets a Department of Homeland Security directive scheduled to take effect on September 18.

Under the updated framework, immigration adjudicators are granted sweeping discretion to weigh an applicant's historical or prospective receipt of means-tested benefits, including Medicaid, food stamps under the Supplemental Nutrition Assistance ...