Ismail Ajjawi, a 17-year-old refugee living in Lebanon, said he was questioned for hours after arriving at Boston Logan International Airport on Friday night and was sent back.
Ajjawi, who was awarded the New Hope Fund undergraduate scholarship by US non-profit Amideast, said his visa was cancelled after immigration officials searched his phone and laptop, and confronted him about his friends' social media posts sharing their political views that oppose the US.
Despite his protests that he had nothing to do with the posts, he was found "inadmissible" to the US, media reports said. Ajjawi intended to study Chemical and Physical Biology at the university.
Explaining the incident, Ajjawi said that after landing he and several other international students faced questioning from immigration officials. But he was held back while his peers were allowed to go.
He said that an immigration officer continued to question him about his religion and religious practices in Lebanon. That officer then asked the student to unlock his phone and laptop and searched them for five hours, according to student newspaper Harvard Crimson.
"When I asked every time to have my phone back so I could tell them about the situation, the officer refused and told me to sit back in (my) position and not move at all," Ajjawi said.
"After the 5 hours ended, she called me into a room, and she started screaming at me. She said that she found people posting political points of view that oppose the US on my friend(s) list."
Ajjawi said he replied to the woman that the political posts were not his own.
Despite his defence, the immigration officer cancelled Ajjawi's visa and told him he would be deported. Ajjawi was allowed a phone call to his parents before he returned to Lebanon.
Ajjawi said he spent a total of eight hours in Boston, which has nearest airport to the Cambridge, Massachusetts university, before he was forced to leave.
He is in contact with a lawyer and the university with the hopes of resolving his visa before classes start on September 3.
Customs and Border Protection (CBP) spokesperson Michael McCarthy said the decision was made "based on information discovered during the inspection".
McCarthy declined to comment on the specifics of the case, citing confidentiality clauses.
Harvard said "the university is working closely with the student's family and appropriate authorities to resolve this matter" before classes begin.
( With inputs from IANS )