The incident began on Tuesday morning when border agents encountered two men carrying backpacks five miles (8km) east of Sumas, Washington, in the US.

Authorities say agents interrupted an attempt to smuggle a load of MDMA, or ecstasy, from Canada to San Francisco.

Two others were arrested and accused of planning to transport the drugs.

On Tuesday morning, US border agents ordered the two men they encountered near the border to halt, officials said.

One of the men dropped his backpack, fired a weapon at the agents, and ran, according to a criminal complaint filed in US federal court in Washington on Wednesday.

The officers took the other man, identified as Jeffrey Laviolette, into custody immediately.

Canadian and US police searched for the fugitive on foot and by helicopter, putting up road blocks.

Nathan Hall, a Canadian citizen, was arrested by the Abbotsford Police Department in British Columbia early on Wednesday morning.

According to border patrol agents, the backpacks Mr Hall and Mr Laviolette were carrying contained a total of 58lb (26kg) of ecstasy.

Also inside one backpack was a California driver's licence with the name of William Nickerson but a picture of Nathan Hall, the complaint alleges.

Investigators later arrested a Bellingham, Washington woman, Kali Henifin, who they say planned to pick the two men up at the border. They also arrested her boyfriend, Ryan Lambert, who allegedly told officers he was to be paid $11,000 (£7,270) to drive the drugs to San Francisco.

Ms Henifin told agents they had been monitoring police radio communication on a mobile phone when they heard a report of a shooting and left the area, according to the complaint.

The three defendants in US custody face conspiracy as well as drug possession and distribution charges.

The wooded area a few miles east of a highway border crossing is a well-known smuggling route for drugs and firearms, and a spokeswoman for the US attorney for the Western District of Washington told the BBC smuggling prosecutions are "a large part of our practice".