Lisa Lapin, a senior communications official at Stanford University, also denied that such an arrangement exists and said the purported acceptance letter was not issued by Stanford.

In an e-mail to the Chosun Ilbo, Harvard public affairs official Anna Cowenhoven said that no joint program exists allowing a student to spend one or two years at Stanford and the rest at Harvard. She added the acceptance letter Kim produced as evidence is a forgery.

Sara Kim, a student at Thomas Jefferson High School for Science and Technology in Virginia, has claimed that the two top universities competed to scout her, and that they set up a special option allowing her to study at both universities and then decide where she wants to graduate.

Harvard and Stanford universities have denied Korean media reports that they have created a special joint study program for a Korean math prodigy.

Kim and her family insist the story is true. Her father Kim Jung-wook, an executive at global online gaming company Nexon, told the Chosun Ilbo by phone, "I will explain once I find out what has happened in the U.S."

He added, "As far as I am aware, the teacher in charge of admissions at her high school was also informed of her acceptance by Harvard online. We will unveil all the letters and documents we exchanged with both universities."

Asked whether he might have been cheated by a broker, Kim said no broker was involved. Kim's relatives in the U.S. visited Kim on Tuesday and confronted her, but she reportedly denied lying and insisted that she had indeed been admitted to both universities.

Kim's story was first published in a Korean newspaper in the U.S. on June 2 and spread to Korean media on June 4 and 5. They did not check the facts with the universities before publishing because U.S. universities do not normally disclose the outcome of applications to a third party.

But once her story was covered in the Korean press, Korean students and parents at Thomas Jefferson High School started to raise questions. A highly competitive state school with a high ratio of graduates entering prestigious universities, Jefferson has a large percentage of Korean students.

While the Chosun Ilbo was verifying her story, it received an e-mail in Cowenhoven's name on Monday which stated that Sara Kim had indeed been accepted by Harvard.

But Cowenhoven a day later confirmed that this e-mail too was a fake.