"Sadly, we did lose one life. While we continue to search the site, at this time we are hopeful that there are no other people trapped in the structure," tweeted New York Mayor Eric Adams late Tuesday afternoon, adding five others were rescued by first responders.

The four-story structure on Ann Street, about half a mile (0.8 km) from the New York Stock Exchange, partially collapsed shortly after 4 p.m., killing at least one worker and injuring five others who were in the building, local officials told a press conference at the scene.

New York Fire Department had ordered all their initial responders out of the building, and a robotics unit had been deployed to check the site because of unstable conditions of the fallen structure.

Pace University announced that two nearby buildings had been evacuated and all classes were canceled due to the collapse.

The collapse was swift and without warning, said eyewitnesses.

"It felt like an earthquake," Liam Gaeta, a Pace University student, told an ABC News affiliate. He said he heard "a large noise and a big rumbling, and then we all got evacuated."