Mr. Sperling’s tourist visa, which was valid until June 18, 2015, now has the word “canceled” stamped atop it in blue ink. Officers also scrawled a black X across the visa.

Image Ilham Tohti, left, and Elliot Sperling in August 2012. Mr. Sperling, who teaches Tibetan history, said he believed that China was punishing him for his backing of Mr. Tohti. Credit... Elliot Sperling

“I call it my Chinese Communist Party Human Rights Award,” Mr. Sperling said.

“There was obviously an order about me entered into the database,” he added. “I saw no point in arguing. I mean, I had a pretty clear notion about why I was being denied entry. For me, it was clearly about Ilham.”

When asked on Monday about Mr. Sperling’s case, a police officer surnamed Cheng who had answered the telephone at the visa office of the Public Security Bureau said he had not heard of it. A Foreign Ministry employee at the ministry’s press center also said she had no information.

The United States Embassy in Beijing declined to comment.

Mr. Sperling said he did not believe his scholarship on Tibet, also a delicate issue for the Chinese government, was the main factor. Until now, Mr. Sperling had traveled often to China on tourist visas. He made a trip in 2010 at the invitation of Chinese scholars hosting a private conference on Tibet. In 2011, Mr. Sperling came to here on a work visa to take up a post of about four months as a visiting scholar at Peking University. During that period, he gave academic lectures on Tibet around Beijing, including at Renmin University and at the Chinese Academy of Social Sciences.

Mr. Sperling is the latest Western scholar to join a list of academics denied access to China. Perry Link and Andrew J. Nathan, two professors in the United States who coedited “The Tiananmen Papers,” an inside look at the 1989 Tiananmen Square crackdown and massacre, cannot get visas to enter China. Orville Schell, who also worked on the book, can get visas only for brief visits.

Most notably, 13 scholars who contributed to a 2004 anthology on Xinjiang were put on a Chinese visa blacklist. Only about four or five have managed to get a Chinese visa in recent years.

One of the authors, Gardner Bovingdon, is a colleague of Mr. Sperling in the department of Central Eurasian studies at Indiana University. In May 2013, he received a Chinese visa after friends lobbied Chinese officials on his behalf. He landed in Beijing a month later, but was turned away by border officers at the airport in the same manner in which Mr. Sperling was rejected on Saturday, Mr. Bovingdon said in a telephone interview from Kazakhstan, where he has been doing research during his long ban from China.