A dead body was discovered lying in the grass at Union Square Park on Thursday afternoon, police said.

Authorities were called shortly after noon to the park near East 15th Street and Union Square West, where they found the unidentified man unresponsive, police said and photographs show.

He was pronounced dead at the scene.

Authorities believe the victim — who showed no obvious signs of trauma  — was homeless, sources said.

Additional reporting by Kevin Fasick