The men were approached by an attacker from behind and shot both in the head on Saturday in the Ozone Park neighbourhood of Queens, a police spokesperson said.
Imam Maulama Akonjee, 55, moved to the city from Bangladesh two years ago and his assistant, 64-year-old Thara Uddin, was critically injured and later on succumbed to his injuries in hospital, reports in New York said.
Both were killed while walking home from afternoon prayers at a mosque.
Police said no arrests had been made.
The suspect was seen by witnesses fleeing the scene with a gun in his hand, police added.
“He would not hurt a fly,” Imam Akonjee’s nephew Rahi Majid, told the New York Daily News. “You would watch him come down the street and watch the peace he brings.”
A large number of Muslims gathered at the murder scene, denouncing the shooting as a hate crime.
