NEW YORK — Columbia University said Friday that it will strengthen its procedures after it accidentally sent acceptance notices to 277 prospective students and had to recall them.

Columbia said the e-mails, sent Wednesday, ‘‘incorrectly implied’’ that the applicants had been accepted into the master’s program of its School of Public Health.

The university said it quickly discovered its mistake and sent follow-up e-mails within an hour.

Vice Dean for Education Julie Kornfeld said Columbia apologized. She said the university values the applicants’ ‘‘energy and enthusiasm’’ and regrets the ‘‘stress and confusion’’ the mistake caused.

Associated Press