Zhai Tiantian, a Chinese student charged as a "terrorist" in the US, demonstrates to a reporter on Thursday in Beijing how he was handcuffed while in the US.

Eight years ago, Zhai Tiantian left China to pursue higher education in the United States. Three days ago, the doctoral candidate returned to his home country with a tag of "potential terrorist" on his head.

Zhai, 27, a former student at the New Jersey-based Stevens Institute of Technology, was doing his PhD when the university suspended him in March, citing major violations of the code of conduct for students as the reason.

Zhai hit the headlines in the American and Chinese media following his arrest on April 15 on charge of terrorism.

The university reported to the police that Zhai made a phone call threatening to "burn down the university building" - an allegation Zhai vehemently denied.

"I never threatened to burn down the school building," Zhai, a native of Xi'an, capital of Shaanxi province, told China Daily in Beijing.

He said that a verbal dispute with Joseph Staley, the assistant vice-president of the university, led to the controversy.

"He questioned my financial situation and was looking for an excuse to kick me out of school," Zhai said.

On April 14, Zhai received a letter from Staley. "It said that I was to leave the US in a week and that my student visa would be revoked," Zhai said.

"So, I called the school the following day, and my exact words were: 'I am going to burn Stevens (Institute of Technology) to the ground in the media and court.' They took what I said out of context.

"I never threatened to burn the school to the ground or hurt anybody."