International students will be forced to leave the U.S. or transfer to another college if their schools offer classes entirely online this fall, under new guidelines issued Monday by federal immigration authorities.

The guidelines, issued by U.S. Immigration and Customs Enforcement, provide additional pressure for universities to reopen even amid growing concerns about the recent spread of COVID-19 among young adults. Colleges received the guidance the same day that some institutions, including Harvard University, announced that all instruction will be offered remotely.

President Donald Trump has insisted that schools and colleges return to in-person instruction as soon as possible. Soon after the guidance was released, Trump repeated on Twitter that schools must reopen this fall, adding that Democrats want to keep schools closed “for political reasons, not for health reasons.”

“They think it will help them in November. Wrong, the people get it!” Trump wrote.

Under the updated rules, international students must take at least some of their classes in person. New visas will not be issued to students at schools or programs that are entirely online. And even at colleges offering a mix of in-person and online courses this fall, international students will be barred from taking all their classes online.

It creates an urgent dilemma for thousands of international students who became stranded in the U.S. last spring after the coronavirus forced their schools to move online. Those attending schools that are staying online must “depart the country or take other measures, such as transferring to a school with in-person instruction,” according to the guidance.

Many of the more than 1000 Zimbabwean students at American universities may have to return home following the new provision.

According to a fact sheet compiled by Open Doors a US Government-funded platform that tracks foreign students that country, Zimbabwe has around 1 343 students studying in the US.

The move has drawn criticism for the Trump administration with critics arguing that deportations on the laid basis are not justified.

Writing on her Twitter handle, Elizabeth Warren, a United States senator belonging to the Democratic Party described the move as being cruel.

“Kicking international students out of the US during a global pandemic because their colleges are moving classes online for physical distancing hurts students. It is senseless, cruel and xenophobic,” Warren said.

Two leading US universities, Havard and Massachusetts Institute of Technology, have already filed a lawsuit challenging the legality of the move.