The FBI is investigating a Border Patrol agent-involved shooting, according to a statement from the Vermont State Police.

       A Border Patrol agent who was assigned to the agency's Swanton Sector, which monitors the Vermont-New Hampshire-New York border, was fatally shot in the line of duty, a Customs and Border Protection spokesperson told ABC News in a statement.

       The incident occurred Monday around 3:15 p.m. on Interstate 91 in Coventry, Vermont, police said.

       The FBI said in a statement Monday evening that one subject was killed in addition to the border agent.

       "Another subject was injured and is in custody," the statement added.

       Further details surrounding the incident are not yet clear.

       Acting Secretary of Homeland Security Benjamine Huffman released a statement following the shooting, saying, "Every single day, our Border Patrol agents put themselves in harm’s way so that Americans and our homeland are safe and secure. My prayers and deepest condolences are with our Department, the Agent’s family, loved ones, and colleagues,"

       The section of the highway where the incident occurred has been temporarily closed, police said.

       This is a developing story. Check back for updates