A man sitting inside a white Mercedes was found dead Saturday afternoon, shot in the head following an argument, police said.

Cops responded to the Upper West Side around 12:30 p.m. for reports of a shooting at West 102nd Street and Amsterdam Avenue.

The 27-year-old man was shot after what started as an argument in the middle of the day, police said.

No suspect description was immediately available, but police said the gunman fled the scene and no arrests were made several hours later.

The investigation is ongoing.