Mr Han then got to his feet and struggled to get out of the way of the oncoming train.
"The most painful part was I could see him getting closer to the edge. He was getting so close," Mr Abbasi said.
Mr Han was dragged by the train 3-5 metres. He later died in Roosevelt Hospital.
Police have since taken a suspect into custody, the New York Times reported.
Abbasi told the Post he was using the flash of his camera to warn the driver, however the published photo has been widely condemned by the Post's readers and other media.
"Why didn't the person help? How many pictures did they take? 3-4 pictures. And nobody tried to help. Not one person. The pictures sure shows that much. What an age we live in when getting the picture is more important! I am appalled," Post reader Joseph Monte wrote beneath the online story.
Another reader, Mary Kate, was also disgusted.
"How tasteless of the NY Post to publish such a grusome picture for this mans family to see. No one helped this man there were numerous videos and pictures being snapped, yet not one person tried to help save him [sic]."
Poynter senior faculty Kenny Irby said the paper's editors should be condemned, rather than the photographer.
"I get that the photographer, Mr. Abbasi, made a decision to document the imminent demise of Mr. Ki Suk Han, because he may have not been strong enough to lift the injured man from the track himself and thus he made a decision to document after attempting to warn the conductor by "rapidly flashing" his camera's flash unit," Mr Irby said.
"My problem thus is with the publication's editors, who clearly had alternative photographs to use and chose to use the most disturbing."