President Donald Trump's immigration restrictions were temporarily blocked nationwide by a federal judge who said the states of Washington and Minnesota could sue claiming their residents were harmed by the ban.

The ruling came after a federal judge in Boston on Friday refused to extend a temporary ruling blocking enforcement of Trump's ban on immigrants from seven Muslim-majority countries at Boston's airport. The administration has also been sued over the order in Brooklyn, New York, Los Angeles and Alexandria, Virginia.

US District Judge James Robart in Seattle rejected a request by the federal government to put his temporary restraining order on hold. The judge told them he would help expedite an appeal.

Robart's ruling is among the most comprehensive legal admonishments of Trump's January 27 executive order prohibiting immigrants from Iran, Iraq, Syria and four other nations from entering the US for 90 days.

The court order, effective immediately, will remain in place until the judge considers a motion to permanently invalidate the president's order, Washington State Attorney general Bob Ferguson said in a statement.

Earlier this week Trump fired the acting US attorney-general for ordering the government's lawyers not to defend the travel ban in court.