(CNN) -- The United States lodged a "strong protest" with Vietnamese authorities after its diplomat was manhandled by police, the State Department said.
The State Department was trying to get more information about the incident that occurred Wednesday between U.S. envoy Christian Marchant and Vietnamese authorities, said State Department spokesman Mark Toner.
"Our U.S. diplomat, Christian Marchant, was injured -- not seriously, but he was injured during that incident," Toner said Thursday. "We have officially registered a strong protest with the Vietnamese government, in Hanoi as well as with the Vietnamese ambassador here in Washington, and we're waiting for a full explanation of what happened."
The incident occurred after Marchant tried to visit dissident Catholic priest Nguyen Van Ly in central Vietnam, Toner said.
"He was attending a prearranged meeting with Father Ly in Hue," Toner said. "Again, we're looking for a full explanation. He was injured. He is up and walking around now, but he was injured during the incident."
Vietnamese officials could not be reached for comment.