Hundreds of demonstrators at about 20 universities across the United States have reportedly been arrested as protests against Israeli attacks on Gaza expand.

Columbia University in New York had warned students who had pitched tents on campus that they would be suspended if they did not disperse by 2 p.m. Monday.

The move drew more students who marched and chanted that they would not stop.

A student organizer said the university had not made significant concessions to their demand of divestment from companies with links to Israel. She said they will stand in solidarity with other student movements across the country.

The New York Times reports that more than 800 students at roughly 20 universities in 16 states have been arrested.

Demonstrators were also arrested at the University of Texas at Austin on Monday after a scuffle between police and students.

People other than students have been joining demonstrations at campuses across the country, and discrimination against Jewish students is being reported.

US media reports say the situation could swiftly become more tense if universities respond forcefully.