International students studying in the United States on an F-1 or M-1 student visa won't be able to continue their studies in the fall if their school only offers online classes, according to an announcement from the U.S. Immigration and Customs Enforcement (ICE).

The ruling comes as schools across the country attempt to navigate how to safely reopen this fall as COVID-19 cases continue to tick upward in many areas.

Students enrolled in a school "operating entirely online" must either leave the country or transfer to a school that is offering in-person classes, ICE said.

"If not, they may face immigration consequences including, but not limited to, the initiation of removal proceedings," a news release said.

The Department of Homeland Security's Student and Exchange Visitor Program (SEVP) normally limits the number of online classes a nonimmigrant student can take under its student visa program. SEVP officials had relaxed those limits for the spring and summer semesters due to the coronavirus, but the new order eliminates those temporary exemptions for the fall 2020 semester.

The University of Southern California announced earlier this month that undergraduate students will "primarily or exclusively" be taking online classes during the fall semester and that "on-campus housing and activities will be limited."

On Monday, Harvard University announced only 40% of undergraduate students would return to campus in the fall.

The ICE announcement said that students enrolled in schools that offer a combination of in-person and online classes will be permitted to continue as long as the school certifies that the program is not all online, that the student is not exclusively taking online classes, and that "the student is taking the minimum number of online classes required to make normal progress in their degree program."

F-1 and M-1 visas are given to foreign nationals who are pursuing academic or vocational studies in the United States, according to ICE.