Washington state is set to ask for a block on US President Donald Trump's new travel ban, becoming the third state to announce its intention to do so.

Democrat attorneys general in Washington, New York, Oregon and Massachusetts on Thursday (9 March) announced their wish to try to block the revised travel ban, which prevents citizens from six majority-Muslim countries from entering the US.

The previous travel ban, which was blocked by US district court judge James Robart, whose decision was upheld by the ninth circuit court of appeals, also included Iraq in the countries named on the banned list.

However, under the new order, Iraqi citizens will be allowed to travel to the US.

Washington Attorney General Bob Ferguson said he would be filing a motion that would request Robart's confirmation the block applied to the revised travel ban becoming the second state to file a major legal action against it, a day after Hawaii.

Speaking at a press conference reported by The Hill, Ferguson said: "We've won in court, and the president has had to honour those defeats. It's my expectation that we will continue to prevail, and certainly my expectation that the president will continue to respect the decision of the court.

He said that the revised order narrows its impact, but explained "there is still harm", adding "This is effectively a Muslim ban".

His decision has the backing of New York and Oregon attorneys general, who are set to follow suit and fight the second version of the travel ban.

A statement from New York Attorney General Eric Schneiderman said: "President Trump's latest executive order is a Muslim ban by another name, imposing policies and protocols that once again violate the Equal Protection Clause and Establishment Clause of the United States Constitution."

However, the White House appears confident that their second attempt at such a ban will not face the same legal roadblocks as the first, with White House press secretary Sean Spicer telling CNN there was confidence about the new order, which he said was consistent with federal law.