US-Canada border patrol agent killed in shooting

A US border patrol agent who was killed in Vermont during a traffic stop near the Canadian border was a military veteran who worked security duty at the Pentagon during the time of the September 11 attacks, his family says.

"He was a devoted agent who served with honour and bravery," a family statement provided to the Associated Press said.

"He had a tremendous respect and pride for the work he did; he truly embodied service over self."

Agent David Maland was killed on Monday afternoon following a traffic stop, a US Customs and Border Protection spokesperson said in a statement.

A German citizen in the country on what the FBI called a current visa was killed and an injured suspect was taken into custody and is being treated at a local hospital.

The violence temporarily closed part of Interstate 91 about 32km from Canada in Coventry, part of the 27,000-resident community of Orleans County in the Northeast Kingdom section of Vermont that straddles the international border.

Maland, whom the FBI confirmed was a US air force veteran, was killed close to the US Customs and Border Protection's Newport Station, part of the Swanton Sector that he was assigned to.

The sector encompasses Vermont, parts of New York and New Hampshire, and includes 475km of international boundary with Canada.

"US Customs and Border Protection's thoughts and prayers are with Agent Maland's family during this difficult time," the agency said in a statement.

Vincent Illuzzi, the state's attorney in neighbouring Essex County, drove past what appeared to be a US Border Patrol agent traffic stop on I-91 past the Newport exit on Monday afternoon, he said, shortly before authorities reported the shots were fired.

"I'm heading down the road, not much traffic, and I saw them on the right," he told the Associated Press by phone.

The agent was driving an unmarked white pick-up trick with a cab on it and red and blue flashing lights, he said.

The stopped vehicle appeared to be a small, blue car, he said.

The agent was speaking with someone standing in front of his truck, behind the car, he said.

Maland was the first border patrol agent to be killed in the line of duty since Javier Vega Jr was shot and killed near Santa Monica, Texas, in 2014, according to records provided by US Customs and Border Protection.

Vega was initially considered to be off duty at the time of his death but in 2016 it was re-determined to have been in the line of duty, the agency said.

In 2010, Brian Terry 's killing exposed the botched federal gun operation known as "Fast and Furious".

Border patrol Agent Nicholas J. Ivie, of the Brian A Terry Border Patrol Station, was mortally wounded in the line of duty in a remote area near Bisbee, Arizona, in 2012. Border Patrol Agent Isaac Morales was fatally stabbed while off duty in 2017 in Texas.