A law enforcement source tells Eyewitness News the 25-year-old victim suffered superficial stab wounds and is expected to be fine.
The incident happened just after 11:30 a.m. on East 86th Street and 2nd Avenue.
The woman was rushed to Cornell Medical Center with non-life threatening injuries.
The suspect, who witnesses described as being emotionally-disturbed, fled the scene and police were canvassing the area.
He is believed to be a street person, perhaps known to neighbors in the area.
"We think he's a little off, so we really want to get him quickly," said this same source.
The suspect is described as a black male and approximately 5'9"-5'11" with a beard and afro-style hair. He was last seen wearing a maroon shirt and carrying a backpack.
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