A warning to Canadians smuggling batches of "B.C. bud" or other contraband into the United States: Beware the eyes in the sky.

An unmanned plane the U.S. government has been using to patrol North Dakota's northern border since 2009 is now flying along a greater section of America's northern frontier, stretching from Spokane, Washington, to the Lake of the Woods region in Minnesota.

Officials with U.S. Customs and Border Protection say the aircraft can transmit live, streaming video and radar images from above the huge swaths of rugged — and remote — terrain that are a haven for criminals sneaking marijuana and ecstasy into the U.S. and cocaine into Canada.

"We're trying to work the border smarter, not harder," said John Priddy, director of National Air Security Operations Center-Grand Forks in North Dakota, where the aircraft is based. "There's new technology being deployed, which will make it more difficult to conduct illicit activities."

Resembling a giant mechanical wasp, the remote-controlled Predator B — which has a length of 12 metres and a wingspan of 20 metres — can stay in the air for 20 hours at a time and typically flies at about 6,000 metres.

It is equipped with infrared sensors and ground-movement detectors and can produce radar images showing tire tracks, shoe impressions and anything else that looks out of place.

Priddy said officials are not deploying the plane each day with an expectation that they will catch a criminal in the act. Instead, they send the Predator B to specific areas of the border, which have been flagged by authorities, and conduct surveillance missions — sometimes over a period of days.

Priddy said the aircraft has contributed to arrests, though he declined to elaborate because investigations are ongoing.

Similar aircraft have been deployed in Iraq and Afghanistan and along parts of the U.S.- Mexico border. The long-term goal is to have them flying along the entire length of the Canada-U.S. border.

Supt. Warren Coons, director of the RCMP Integrated Border Enforcement Team, said Wednesday he has not received information about the surveillance program's effectiveness and declined to offer a personal opinion.

Coons said there are no plans to adopt such technology in Canada, but he wouldn't discount it, either. He noted Canadian authorities use other forms of visible and covert technology — he declined to say what — at points of entry and in remote sections along the border. Improved communication between U.S. and Canadian authorities has helped to identify vulnerable areas, he said.

Some Canadian residents who live along the border wonder whether the Predator B is anything more than a fancy toy.

In the two years the Predator B has been patrolling the North Dakota-Manitoba border, southern Manitoba legislature representative Clifford Graydon said he's never heard of any arrests linked to the aircraft.

He said his counterparts across the border have told him the machine has had mechanical issues and doesn't perform well in bad weather.

"I'm not certain how effective it's been," he said.

Graydon did acknowledge, however, that the smuggling of drugs and guns is a problem and that the mere publicity of the Predator B could serve as a deterrent.