United States officials denied a Palestinian student's request to enter the country this month.The student was planning to attend classes at Harvard University.Some Americans are calling what happened to himan example of overly invasive safeguards at U.S. border checkpoints.Ismail Ajjawi was refused entry after landing last week at Boston's airport in Massachusetts.The 17-year-old said his denial was linked to political messages published by his friends on social media.A U.S. Customs and Border Protection official, however, would not confirm the information.The official told The Associated Press (AP) that the decision to cancel Ajjawi's visawas based on information discovered during an inspection.The official added, he can still try to reapply for visa to enter the country.Ajjawi told the Harvard University student newspaper that federal agents detained him for eight hours.He said they searched his electronic devices and questioned him about his friends' social media posts.They included "political points of view that oppose the U.S.," he said in a statement."I responded that I have no business with such postsand that I didn't like, (s)hare or comment on themand told her that I shouldn't be held responsible for what others post," Ajjawi wrote.A Harvard University official said the school is working "to resolve this matterso that he can join his classmates in the coming days."AMIDEAST, a not-for-profit organization that awarded Ajjawi a scholarship, is providing legal assistance.Summer Lopez is a senior director with PEN America,a nonprofit organization that works for free speech.She said, "Preventing people from entering the countrybecause their friends critiqued the U.S. on social mediashows an astounding disregard for the principle of free speech."Carrie DeCell is a lawyer with the Knight First Amendment Institute at Colombia University in New York.She said that the incident could result in self-censorship on social media and threaten intellectual freedom.The AP reports a group that calls for stronger immigration laws,the Center for Immigration Studies, did not answer its request for comment.But the administration of President Donald Trump has said the increased searchesare critical to prevent extremists from entering the country.U.S. agents have been inspecting electronic devices and social media posts at border points for some time.In June, the State Department expanded the measures,requiring nearly all foreigners seeking U.S. visas to provide their social media usernames.They also are required to list current and former email addresses and phone numbers.In the past, such information was requested only of individuals identified for more investigation,such as people who had traveled to areas controlled by terrorist groups.It is not clear how many social media searches border officials have carried outsince the new policy took effect.But the agency did conduct more than 33,000 electronic device searchesduring a 12-month period ending in September 2018.That is four times higher than the 8,500 searches conducted three years earlier.The government released those numbers as a result of legal actionby the American Civil Liberties Union and other groups.Ajjawi told The Harvard Crimson newspaper he still hopes to join his classmatesin time for the start of classes next week.His family lives in a camp for Palestinian refugees in the southern Lebanese city of Tyre.