Beijing, China (CNN) -- The U.S. Embassy here says it is "dismayed" by a Chinese court decision sentencing a U.S. citizen to eight years in prison for violating state secrets law.
In a written statement Monday, U.S. Ambassador to China Jon Huntsman called for the release of Dr. Xue Feng, a naturalized U.S. citizen, who in addition to the prison sentence was fined about $29,500 for allegedly providing intelligence abroad.
"I was at the courthouse this morning when Dr. Xue Feng was sentenced to eight years and fined 200,000 RMB. I am disappointed, " Huntsman said in a written statement.
"I believe the time has come for Dr. Xue, who has already been detained for two and a half years, to be released," he said.
Huntsman -- who has visited Xue in prison -- urged Chinese authorities to release the accused U.S. citizen "in the spirit of justice" and to " allow him to be returned home and be reunited with his family."
The University of Chicago's Dr. David B. Rowley, Xue's former professor who has rallied for his release, said he was "shocked" by the sentencing and claims that Xue is languishing in prison on vague charges.
"I find this whole thing just unbelievable in no small part because the rationale is just so thoroughly flawed," Rowley said.
Xue "has always been a straight shooter," Rowley said. "He was not ... a wheeler-dealer type." He is "an honest, hard worker and this came as a real surprise to him as well."
Xue was working in China as a leading geologist for the Colorado-based IHS Consulting firm, a global provider of energy-related information, Rowley said, and the information Xue was privy to did not include state secrets.
While Rowley said he was not privy to the specific database mentioned in Xue's indictment, the University of Chicago professor said the pieces of information commonly contained in such databases are not state secrets.
"These types of databases usually contain information related to the petroleum potential of a given area, and that might include what wells already have been drilled and information on the geology and geophysical or underlying structure of these areas. That's pretty much it," he said.
Xue's job as a leading consultant for IHS involved acquiring and reselling this type of data, Rowley said.
He said that as a petroconsultant, Xue thought he was viewed favorably by the Chinese because he was able to sell to Chinese officials similar data from countries in which the Chinese had drilling interests.
Rowley said Xue had resigned from IHS at the time of his arrest and believed that the warnings issued by Chinese officials concerning the database were not issued against him, but against his employers, he said.
"IHS is extremely disappointed at the news and is very sympathetic to the situation. We are continuing to work with our advisors on the issue," said IHS spokesman Ed Mattix.
CNN producers in Beijing have reached out to Chinese officials for reaction but there has been no official response.
Rowley said U.S. Embassy officials reported Xue was depressed and had been tortured with cigarette burns.
CNN's Helena de Moura, Eve Bower and Mark Bixler contributed to this report