Many international, first-generation and low-income students said they fear losing shelter, medical care and food as universities shut down their campuses in an effort to control the spread of COVID-19, which the World Health Organization declared Wednesday a pandemic.

When the University of Dayton in Ohio announced Tuesday it would close student housing the next day and send students home, some said they were unsure where to go next.

More than 1,000 students gathered in the streets Tuesday night, according to university officials, to express their frustrations.

Police in riot gear responded. Flyer News, the University of Dayton's student-run publication, tweeted a video showing police shooting pepper balls at the crowd. Multiple students were seen vomiting.

"Police initially launched pepper balls, which contain powder with an irritant that disperses quickly, that were unsuccessful in reducing the crowd size," university officials said in a statement.

But students also defended disadvantaged students who could be displaced by housing being shuttered.

"Let us stay," was the one request of students at Amherst College in Massachusetts in a letter to university administrators that, in less than three hours, gained more than 300 signatures from students, faculty and staff.

They expressed concern that the students may not return home safely or could afford the journey. They said traveling, especially through crowded airports and train stations, would put their health at risk, and expose family members and loved ones once they arrived home.

At Harvard College, the school's undergraduate community rallied to provide support for those affected by their college's short-notice decision to shut down student housing.

Dean of Harvard College Rakesh Kurana announced early Tuesday morning that all undergraduate students had to move out - belongings and all - by Sunday for the rest of the spring term and possibly into summer.

When they heard the news, Harvard's students were mostly caught off guard. Some equated the move as an eviction, according to the student-run Harvard Crimson.

Tomasz Wojtasik, a 21-year-old sophomore from Chicago, was getting ready for his first class of the day.

"I was very shocked," he said. "On Monday, we received an email asking us to stay put and avoid travel internationally or domestically if we could. And then all of a sudden, they are asking us to leave campus."

Wojtasik only had 24 hours to apply for an exemption allowing him to stay on campus. He said he is worried that if his application is denied, he will have even less time to figure out accommodations for the rest of the semester.

Low-income students who intended to stay on campus over spring break now need to finance travel plans. International students, or those who live outside the United States, need to make the return trip home.

Wojtasik is working with PRIMUS, a student organization at Harvard that advocates for first-generation students negatively affected by being displaced. First-generation students make up 15% of Harvard's undergraduates; 20% of Harvard students are on full financial aid at the college.

"In addition to costs associated with unexpected flights home, students are being asked to ship or store all of their on-campus belongings with no promised full financial support," PRIMUS's executive board wrote in a statement.

"What's bizarre is that the college is not offering any storage space," Wojtasik said. Harvard students have had to pay for last-minute storage or find other space for their belongings on short notice. Storage costs for dorm room contents can reach more than $100.

Jose Perez, a senior at Harvard studying sociology, and a past president of PRIMUS, said when he heard Harvard was shutting down campus, he was shocked.

"We don't even get snow days," Perez said.

Perez is trying to find storage options for disadvantaged students. He's written letters asking faculty, alumni and students living locally to provide free storage or housing. At one point, Perez said 75 students were collaborating on Google Docs to provide information for students.

"We had an overwhelming response," Perez said.

More than 65 students have offered housing and storage, and more than 15 faculty members offered storage. Alumni has also pitched in. Cambridge, Massachusetts, Mayor Sumbul Siddiqui tweeted contact information to students unable to find housing.

"The Harvard community has really rallied together to help students in need," he said.

"I felt an extreme sadness about leaving. As a senior, this may have been the last time seeing a lot of my friends," Perez said. "The goodbyes I was hoping to do over the last month or two have been shortened to five days."