U.S. officials in Vietnam say they have lodged a formal protest after an American diplomat was manhandled by security forces while trying to visit a prominent dissident.
U.S. embassy officials said Thursday the mistreatment was "a clear violation" of the Geneva conventions, which provide for the protection of diplomats in foreign countries.
U.S. officials would not provide details of the incident, which occurred Wednesday in Hue. But news reports said the embassy's human rights officer, Christian Marchant, was in the central Vietnam city to visit with Nguyen Van Ly, a Roman Catholic priest who is on temporary release from prison for medical care.
The reports say security officers stopped Marchant outside the priest's residence and wrestled him to the ground before driving him away in a police car.
A State Department spokesman in Washington told VOA that a formal protest has also been delivered to the Vietnamese ambassador in the United States, Le Cong Phung.
Ly was sentenced in 2007 to eight years in prison on charges of making propaganda against the state. He was given a 12-month release last year to receive treatment for a brain tumor.
Diplomatic relations between the United States and Vietnam improved strongly in 2010, but human rights issues remain a major source of friction.
The U.S. ambassador in Hanoi, Michael Michalak, said last month that free expression is under attack in Vietnam, with new restrictions on bloggers and Internet cafes and the hacking of critical websites. He said 24 people were arrested and 14 others were convicted last year "for the peaceful expression of their views."
Some information for this report was provided by AP and AFP.