The message was a recorded video that was played on a large screen at the New York Historical Society on Manhattan's Upper West Side.
"All Americans are your brothers and sisters. And each of us must do our part to keep America safe, strong and free," President Trump said. "We share one American heart and one American destiny."
WEB EXTRA: Watch the full message in the video player above
A total of 200 people were named citizens in the ceremony, and hail from 60 different countries.
The ceremony was held in honor of Constitution Day and Citizenship Day, both of which were observed on Sept. 17.