The Museum of Modern Art in Manhattan was evacuated this afternoon after two women were stabbed on the ground floor.
Horrified witnesses said they saw two people being taken out of the building on stretchers.
Both victims are thought to be in a stable condition in hospital, as police launch a manhunt for the suspect.
The man the NYPD are looking for was believed to be wearing a black beanie and a black hoodie.
Police have not identified the victims, and the motive for the assault is not yet known.
Alyssa Katz, deputy editor of New York news outlet The City, tweeted that a ‘stampede; of people were seen ‘fleeing’ the museum.
‘I just spoke with witnesses visiting from Cannes, France. They saw someone stabbed in the underarm on the first floor,’ she wrote.
Several people inside the building filmed the evacuation as they were led outside into the snow by museum staff.
One Twitter user who shared a video of their scape said: ‘Had to evacuate the MoMa.
‘We were locked up in the basement while not knowing what was going on. People were screaming and crying. Police told us to RUN.’