In a series of posts on Twitter, Kyle Kashuv shared several letters he received from Harvard, first notifying him his admission offer was being reconsidered in light of the comments and, later that it was being revoked.

The decision stems from comments that were shared among friends when he was 16, months before the shooting at Marjory Stoneman Douglas High School in Parkland.

Screenshots circulated on social media appear to show the teenager using racial slurs on Google Docs, an online word processor, and in text messages.

The comments include anti-Semitic barbs and repeated use of a slur referring to black people.

The now 18 year old , told Harvard that he "unequivocally" apologises and that the remarks don't represent the person he is today. "I take responsibility for the idiotic and hurtful things I wrote two years ago," he wrote in a letter.

In response, Harvard 's admissions dean William Fitzsimons said the institution was "sorry about the circumstances that have led us to withdraw your admission".

"The committee takes seriously the qualities of maturity and moral character," he added.

Harvard sparked debate in 2017 when it pulled offers from 10 incoming freshmen after they reportedly made racist and sexually offensive comments on Facebook.

Mr.Kashuv said he had been planning to take a year off before starting at Harvard, so he could continue his work promoting school safety.

Now he's "exploring all options," he said, but has missed the deadline for many colleges and already turned down other offers.

Australian Associated Press