A federal judge in New York has struck down a Trump administration policy that suspended visa processing for citizens of 75 countries, ruling that Secretary of State Marco Rubio exceeded his legal authority and that the policy conflicted with federal immigration law.

US District Judge Jeannette Vargas, a Biden appointee, set aside the policy on Friday, finding that it was “contrary to law and in excess of statutory authority”. The ruling affects nationals of countries including Afghanistan, Iran, Russia and Somalia who had been targeted under the administration’s policy over concerns that they could require public assistance in the United States.

Vargas ruled that Rubio lacked the authority to impose a blanket suspension of visas on otherwise eligible applicants based on their nationality. According to the judge, the policy conflicted with the Immigration and Nationality Act by requiring visas to be denied without a specific legal basis.

She also said the measure interfered with Congress’s requirement that consular officers retain primary responsibility and discretion over individual visa decisions.

“Congress imbued these officers with exclusive authority and discretion to determine if an immigrant is eligible for a visa based upon review of specific and detailed criteria set forth in the statute,” Vargas wrote.

The judge said the policy effectively prevented eligible applicants from receiving immigrant visas solely because of their nationality, undermining the statutory system established by Congress.

Two nonprofit organisations and 11 individuals challenged the policy in court. Six of the individual plaintiffs had family members whose visa applications were refused, while five others were outside the US and had filed employment-based petitions to enter the country.

Anna Gallagher, executive director of CLINIC, one of the organisations involved in the case, welcomed the decision, saying it would help families affected by the policy move towards reunification.

Another plaintiff, African Communities Together, also welcomed the ruling. Diana Konate, the group’s deputy executive director for policy and advocacy, called the decision a major victory for the rule of law and said the ban had caused significant hardship for families and communities.

The decision represents a setback for the Trump administration’s immigration policy and places limits on the State Department’s ability to impose broad visa restrictions without a clear statutory basis.

The administration could challenge the ruling, potentially setting up another legal battle over the extent of executive authority over US immigration and visa policy.