Washington (Reuters): President Donald Trump on Friday put a four-month hold on allowing refugees into the United States and temporarily barred travelers from Syria and six other Muslim-majority countries, saying the moves would help protect Americans from terrorist attacks.

In the most sweeping use of his presidential powers since taking office a week ago, Trump paused the entry of travelers from Syria and the six other nations for at least 90 days, saying his administration needed time to develop more stringent screening processes for refugees , immigrants and visitors.

"I'm establishing new vetting measures to keep radical Islamic terrorists out of the United States of America. Don't want them here," Trump said earlier on Friday at the Pentagon. "We only want to admit those into our country who will support our country and love deeply our people," he said.

The order seeks to prioritize refugees fleeing religious persecution, a move Trump separately said was aimed at helping Christians in Syria. That led some legal experts to question whether the order was constitutional.

One group said it would announce a court challenge on Monday. The Council on American-Islamic Relations said the order targets Muslims because of their faith, contravening the U.S. Constitutional right to freedom of religion.

"President Trump has cloaked what is a discriminatory ban against nationals of Muslim countries under the banner of national security," said Greg Chen of the American Immigration Lawyers Association. The bans , though temporary, took effect immediately, causing havoc and confusion for would-be travelers with passports from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.

 

Trump has long pledged to take this kind of action, making it a prominent feature of his campaign for the Nov. 8 election, but people who work with Muslim immigrants and refugees were scrambling on Friday night to determine the scope of the order.

Even legal permanent residents - people with "green cards" allowing them to live and work in the United States - were being advised to consult immigration lawyers before traveling outside the country, or trying to return, said Muslim Advocates, a civil rights group in Washington.

On Friday evening, Abed Ayoub of the American-Arab Anti-Discrimination Committee said he had fielded about 100 queries from people anxious about the order, which he said he believed could affect traveling green card holders, students, people coming to the United States for medical care and others.