The Trump administration’s revised executive order temporarily suspending travel by people from six predominantly Muslim countries could affect an estimated 15,000 international students.

Of those, about 12,000 come from Iran, which is one of the countries named in the ban.

Students who have valid visas are not expected to be affected.

“The new order signed today … [applies] only to foreign nationals outside the United States who do not have a valid visa,” said Department of Homeland Security (DHS) Secretary John Kelly. “It is important to note that nothing in this executive order effects current lawful permanent residents or persons with current authorization to enter our country.”

“If you have a current valid visa to travel, we welcome you,” Kelly wrote in a release from DHS.

However, it remains unclear what impact the order will have on students who will need to renew their U.S. visa to continue their studies.

Peter Asaad, an immigration attorney and partner at Quarles and Brady in Washington, advised that “although the executive order purportedly will not automatically invalidate current unexpired visas, individuals from the six countries should be advised to refrain from exiting the U.S. when possible.”

“And those outside the U.S. should seek to enter as soon as possible until there is greater clarity,” Asaad said.

There are more than a million international students in the U.S., a number that has nearly doubled in the past decade.

Several well-known universities pushed back against the original executive order announced in January, which was later suspended following legal challenges.

Some 17 universities filed legal papers February 13 against the first travel ban, calling it “serious and chilling” to international education. They included Brown, Columbia, Harvard, John Hopkins, Massachusetts Institute of Technology, Princeton, Stanford, Vanderbilt and Yale.

“The new travel ban will surely get litigated,” Asaad said. “The court will look at whether there is a rational basis for the travel ban, which may again stop the president’s action under the same rationale as the Washington District Court’s nationwide ban.”

Students took to social media to air their opinions.

“There have been more deaths from vending machines falling over than from the nationals of 6 Muslim-majority countries,” tweeted Ali Nazari, a student at the University of Texas-Dallas, in response to the latest executive order.

The U.S. green card is available to international students who show exceptional ability in the sciences, arts or business, and who can certify that they have a job offer. The U.S. limits those EB-2 visas to 40,000 holders each year. Students may obtain a green card through family channels, as well, by being the spouse, minor child, married or unmarried son or daughter, or brother or sister of a U.S. citizen who is 21 or older.

They may also be priority workers through an EB-1 visa if they have extraordinary abilities or are outstanding professors or researchers on a tenure track position.

In addition to green card holders, those excluded from the new restrictions are dual nationals using passports from unaffected countries; persons with valid U.S. visas or other travel documents; persons on diplomatic or similar passports; and persons who have been granted asylum in the U.S.

Consular officers may also make exceptions on a case-by-case basis for individuals with business, study or family connections to the United States. Individuals already in the United States are also excluded.

The new order includes a temporary halt to refugee admissions and approval for admissions for 120 days. Some exceptions are possible, but they are limited. The order also calls for refugee admissions for all of 2017 to be capped at 50,000. This could be called a “refugee cap” or “refugee limit.”

Last year, international students added $32.4 billion to the U.S. economy.

VOA interns Devon Sgubin, Elly Kim and Hitender Rao contributed to this report. Hitender is a journalist with Hindustan Times and is studying in the U.S. as a Fulbright Fellow.