Maryland federal judge Theodore Chuang said the ban of travelers from six majority-Muslim countries and North Korea, and on many officials from Venezuela, essentially had not changed from the first two versions, which were shot down in lower courts as discriminating against a single religion.
He pointed out, as in earlier rulings, that Trump had repeatedly promised a ban on Muslims coming into the country during last year's presidential election. Chuang was the second judge this week to order a block on the open-ended ban, issued in a White House executive order in September and which was to come in effect on Wednesday.
On Tuesday, Hawaii federal district judge Derrick Watson also objected to the ban, saying it illegally discriminated against the entire populations of six countries -- Iran, Libya, Somalia, Sudan, Syria and Yemen -- and would not, as it claimed, add to US national security.
Trump has battled with the courts since the first version of the ban, and in June finally gained Supreme Court approval to implement an amended second version for 90 days, which ended last month.
On Tuesday the White House said it would fight the newest ban by Watson, pointing to yet another likely fight in the Supreme Court.
"We are therefore confident that the judiciary will ultimately uphold the president's lawful and necessary action and swiftly restore its vital protections for the safety of the American people," the White House said.