HONOLULU - Hours before it was to take effect, US President Donald Trump's revised travel ban was put on hold Wednesday by a federal judge in Hawaii who questioned the government's argument that the measure was motivated by national security concerns.

US District Judge Derrick Watson also said Hawaii would suffer financially if the executive order blocks the flow of students and tourists to the state and concluded that Hawaii is likely to succeed on a claim that the ban violates First Amendment protections against religious discrimination.

Watson issued his 43-page ruling less than two hours after hearing Hawaii's request for a temporary restraining order to stop the ban's implementation.

The ruling came as opponents renewed their legal challenges across the country, asking judges in three states to block the executive order that targets people from six predominantly Muslim countries.

Trump, speaking at a campaign-style event in Nashville, Tennessee, ridiculed the decision.

"The order he blocked was a watered-down version of the first order, that was also blocked by another judge and should have never been blocked to start with," the president said.

"This new order was tailored to the dictates of the Ninth Circuit's, in my opinion, flawed ruling in the opinion of many, an unprecedented judicial overreach," he said.

Trump said it was up to the president, "whoever he or she is", to decide who should be allowed into the country.

"Fortunately, it will not be Hillary she," he joked to the audience.

"If he thinks there's danger out there, he or she, whoever is president, can say, 'I'm sorry folks, we got enough problems,'" Trump said.

"You don't think this was done by a judge for political reasons, do you? No!" Trump said. "We're going to fight this terrible ruling all the way up to the Supreme Court. Regardless, we're going to keep our citizens safe, believe me."

More than half a dozen states are trying to stop the ban. Federal courts in Maryland, Washington state and Hawaii heard arguments about whether it should be allowed to take effect early Thursday.

Watson was nominated to the federal bench by President Barack Obama in 2012 and is currently the only native Hawaiian judge serving on the federal bench and the fourth in US history. He received his law degree from Harvard in 1991.

In Maryland, attorneys told a federal judge that the measure still discriminates against Muslims.

Government attorneys argued that the ban was revised to address legal concerns, including the removal of an exemption for religious minorities from the affected countries.

"It doesn't say anything about religion. It doesn't draw any religious distinctions," said Jeffrey Wall, who argued for the Justice Department.

Attorneys for the ACLU and other groups said that Trump's statements on the campaign trail and statements from his advisers since he took office make clear that the intent of the ban is to ban Muslims.

Trump policy adviser Stephen Miller has said the revised order was designed to have "the same basic policy outcome" as the first.

The new version of the ban details more of a national security rationale. It is narrower and eases some concerns about violating due-process rights.

It applies only to new visas from Somalia, Iran, Syria, Sudan, Libya and Yemen and temporarily shuts down the US refugee program. It does not apply to travelers with visas.

"Generally, courts defer on national security to the government," said US District Judge Theodore Chuang. "Do I need to conclude that the national security purpose is a sham and false?"