COVENTRY, Vt. (AP) — A U.S. Border Patrol agent was killed Monday in northern Vermont south of the Canadian border, authorities said.

The Department of Homeland Security’s U.S. Customs and Border Protection said in a statement that the agent was killed in the line of duty, although it did not provide details.

Vermont State Police said the shooting happened Monday afternoon on Interstate 91 in Coventry, about 20 miles (32 km) from the Canadian border. State police officers were assisting federal authorities including the FBI and Homeland Security.

A portion of the highway was closed in both directions for about two hours afterward. The northbound lane reopened just after 5 p.m.

Coventry is close to the U.S. Customs and Border Protection’s Newport Station, part of the Swanton Sector, which encompasses Vermont and parts of New York and New Hampshire. The area includes 295 miles (475 kilometers) of international boundary with Canada.