Concerns with smuggling and terrorism have led to heightened security along U.S borders. Mike O'Sullivan reports from Seattle.

Security cameras on US-Canada border

The U.S. southern border with Mexico has hundreds of kilometers of high fencing, with more planned, but there is little to mark parts of the U.S. northern border.

A small fence is all that separates the U.S. town of Blaine, Washington, from a Canadian highway.

Border fence at Blaine, Washington

Concerns with terrorism have led to added layers of security at border checkpoints, where people crossing over are photographed and questioned.

Customs and Border Protection agents check drivers, passengers and cargo. They are looking for contraband, undeclared goods, and people, including terrorists, trying to enter the country illegally. Supervisory agent Larry Nichols says the screening process is both an art and a science.

Larry Nichols

New technology is also helping safeguard the border.

In this area near Seattle, a network of cameras, seismic motion detectors and banks of computer monitors help agents keep track of the border. Employees monitor video screens, and dispatch agents where they are needed.

Audrey Block lives meters from the border, where things are quiet now. She says before the security upgrade, this area was popular with Canadian drug smugglers.

Audrey Block

Port of Seattle

Officials at the border say they are working to strike a balance, extending security while maintaining an open border with Canada.