The United States is deeply troubled by an eight-year prison sentence that was handed to a Vietnamese Catholic priest last week, said State Department spokesman Sean McCormack on Friday.

“This is something that is certainly not a positive development,” McCormack told The Associated Press. "Absolutely. It's a negative development."

Fr. Thadeus Nguyen Van Ly, 60, was sentenced Friday by Vietnamese provincial court Judge Bui Quoc Hiep for committing "very serious crimes that harmed national security," in his quest for Democracy in Vietnam, reported the Associated Press.

These crimes include planning to boycott upcoming legislative elections, disseminating anti-government documents and communicating with pro-democracy activists overseas. Authorities claimed the priest was also plotting to merge his Vietnam Progression Party with overseas democracy activists and to overthrow the current communist government.

The court also sentenced four co-defendants who were accused of being Fr. Ly's accomplices. The defendants were not represented by a lawyer. Fr. Ly was not in the courtroom when the sentences were read.

McCormack said Fr. Ly’s sentencing follows reports of other episodes of harassment, detention and arrest "of individuals peacefully exercising a legitimate right to peaceful speech."

Fr. Ly is well known to Vietnamese authorities as a dissident. He was previously jailed twice for pro-democracy activities and spent more than a decade in prison for his political activism. He was sentenced in 2001 for 15 years, but was released in 2005 after Western governments and international human rights groups protested.

McCormack said U.S. officials, including Secretary of State Condoleezza Rice, have brought up Fr. Ly's case with Vietnamese officials, among them Foreign Minister Pham Gia Khiem.

McCormack told the AP that the U.S. will be “watching the situation very closely.”