Hundreds of demonstrators marched downtown while a spokeswoman for President Trump said the president had the authority to detain Mahmoud Khalil.

The White House complained that Columbia University is refusing to help federal agents find people being sought as part of the government’s effort to deport participants in pro-Palestinian demonstrations.

White House Press Secretary Karoline Leavitt alleged that Khalil had played a role in organizing demonstrations at which fliers were handed out bearing a logo for Hamas, which she did not display.