WASHINGTON — President Donald Trump signed a new travel ban Monday that administration officials said they hope will end legal challenges over the matter by imposing a 90-day ban on the issuance of new visas for citizens of six majority-Muslim nations.

In addition, the nation’s refugee program will be suspended for 120 days, and it will not accept more than 50,000 refugees in a year, down from the 110,000 cap set by the Obama administration.

Members of Maine’s congressional delegation said they were pleased with some of the changes made by the Trump administration compared with the president’s prior ban but said they were either against the ban or still reviewing it.

Trump signed the new ban out of public view, according to White House officials. The order will not take effect until March 16, officials said.

The new guidelines name six of the seven countries included in the first executive order, but leave out Iraq. That nation will increase cooperation with the United States on additional security vetting under separate negotiations and its citizens are not subject to the new order, according to a fact sheet provided by the administration.

A Department of Homeland Security official, speaking on the condition of anonymity on a call with reporters, said Iraq was “treated differently” in part because the country had agreed to “timely repatriation” of their citizens if they were ordered deported from the United States.

The new order provides other exceptions not contained explicitly in previous versions: for travelers from those countries who are legal permanent residents of the United States, dual nationals who use a passport from another country and those who have been granted asylum or refugee status. Anyone who holds a visa now should be able to get into the country without any problems, though those whose visas expire will have to reapply, officials said.

Members of Maine’s congressional delegation had mixed reactions to the development.

Republican U.S. Sen. Susan Collins said she was pleased that it addressed some of the concerns she and others had with the original.

“The new order now exempts green card and visa holders, permits Iraqi translators and others who assisted our military to enter our country on special immigration visas and eliminates the ill-conceived religious test that was included in the original order,” said Collins in a written statement. “I will continue to analyze the impact of the executive order.”

Independent U.S. Sen. Angus King said Trump’s travel ban exacerbates homeland security efforts.

“Rather than sow divisions that will pose dangers to national security, and punish innocent families seeking refuge from violence, the president should work to improve counterterrorism partnerships with the Muslim world and also work with Congress to further strengthen entry and exit procedures, like the visa waiver program, which I continue to believe represents a serious security vulnerability,” said King in a written statement.

The state’s two other members of Congress split on it in statements. U.S. Rep. Chellie Pingree, a Democrat from the 1st District, called the revised order “deeply unsettling” and said it’s “wrong and un-American to ban people from coming to our nation to build a better life.”

U.S. Rep. Bruce Poliquin, a Republican from the 2nd District, said it was an effort to improve homeland security and said he was “pleased to see there is a system in place to deal with case by case waivers so there is a process allowing those to enter who should pose no threat.”

Maine has approximately 12,500 African refugees, including some from Somalia and Sudan, according to the Immigrant Resource Center of Maine.

“It hurts my heart for the country that I love to reject me and my family with this Muslim ban, which will keep others from Somalia from finding opportunity in America,” said Fatuma Hussein, executive director of the Immigrant Resource Center of Maine, who came to the U.S. in 1993.

Alison Beyea, executive director of the ACLU of Maine, said the order is unconstitutional and that her organization “will continue to challenge it in court.”

Officials also attempted to lay out a more robust national security justification for the order, claiming that it was needed because 300 people who entered the country as refugees were the subject of counterterrorism investigations.

The officials, though, declined to say from which countries those people came, and they declined to detail the people’s current immigration status.

A Department of Homeland Security report assessing the terrorist threat posed by people from the seven countries covered by President Trump’s original travel ban had cast doubt on the necessity of the executive order, concluding that citizenship was an “unreliable” threat indicator and that people from the affected countries have rarely been implicated in U.S.-based terrorism.

The Department of Homeland Security official, speaking on the condition of anonymity, criticized the report as being incomplete and not vetted with other agencies, and he also asserted the administration should not be pressed by the judiciary to unveil sensitive national security details to justify the ban.

“This is not something that the Department of Justice should have to represent to a federal-district court judge,” the official said.

The order represents an attempt by the Trump administration to tighten security requirements for travelers from nations that officials said represent a terrorism threat. A more sweeping attempt in January provoked mass protests across the country as travelers en route to the United States were detained at airports after the surprise order was announced. The State Department had provisionally revoked tens of thousands of visas all at once.

Officials sought to dismiss the idea that there would be any confusion surrounding the implementation of the new order. Officials said they delayed implementation so the government could go through the appropriate legal processes and ensure that no government employee would face “legal jeopardy” for enforcing the order.

“You should not see any chaos, so to speak, or alleged chaos, at airports. There aren’t going to be folks stopped tonight from coming into the country because of this executive order. If they are, it’s pursuant to our ordinary screening procedures,” the Department of Homeland Security official said. “We’re going to have a very smooth implementation period.”

A federal district judge in Washington state first suspended the travel ban Feb. 3, and a three-judge panel of the U.S. Court of Appeals for the 9th Circuit later upheld that freeze.

That setback was a blow to the White House, which was criticized for failing to include lawmakers and stakeholders in its deliberations.

The revisions to the order will make it more defensible in court — limiting the number of people with standing to sue — though they might not allay all the concerns raised by judges across the country. The three-judge panel with the 9th Circuit Court of Appeals, for example, said that exempting green card and current visa holders from the ban would not address their concern about U.S. citizens with an interest in noncitizens travel.

The administration, too, will have to wrestle with comments by the president and top adviser former New York City Mayor Rudolph W. Giuliani seeming to indicate the intent of the order was to ban Muslims from entering the United States, which could run afoul of the Establishment Clause of the First Amendment.

On the campaign trail, Trump called for a “total and complete shutdown of Muslims entering the United States.” After the election, Giuliani said, “So when [Trump] first announced it, he said, ‘Muslim ban.’ He called me up. He said, ‘Put a commission together. Show me the right way to do it legally.’”

A federal judge in Virginia referenced those comments in ordering the ban frozen with respect to Virginia residents and institutions, calling it “unrebutted evidence” that Trump’s directive might violate the First Amendment.

The new order drew condemnation from immigrant rights advocates.

“The president has said he would ban Muslims, and this revised version — in these preliminary fact sheets — still does that, even if they have removed Iraq from the list,” said Gregory Chen, director of advocacy for the American Immigration Lawyers Association. “In its oral argument before the 9th Circuit, the government was unable to provide any evidence to the 9th Circuit that acts of terrorism had been committed by the nationals of seven countries initially designated. That was an embarrassment, but now weeks later, in these preliminary fact sheets, they still have not explained why people from these countries pose risk to America’s national security.”

The Department of Homeland Security official disputed that the order targeted Muslims.

“This is not a Muslim ban, in any way shape or form,” he said, noting there were “hundreds of millions” of Muslims who were not subject to the order.

BDN writer Michael Shepherd contributed to this report.