The U.S. Customs and Border Protection has used the remote-controlled Predator B on the Mexican border for several years. The agency began flying the first Predator on the northern border out of Grand Forks Air Force Base in North Dakota in February and now is testing the aircraft along Lake Ontario and the St. Lawrence River.

“Lessons learned during this deployment will be a foundation for our future basing and deployment strategies for our unmanned aircraft system,” said Michael Kostelnik, the agency’s assistant commissioner for air and marine operations.

The unmanned aircraft has been temporarily based at the U.S. Army’s Wheeler-Sack Airfield since June 8 and will fly patrols from Fort Drum until the end of the month, said John Stanton, executive director of the CBP’s National Air Security Operations.

The Predator flies at about 19,000 feet and can stay aloft for up to 18 hours. It can take high definition and infrared video of anything within a 25-mile radius and has extra-sensitive radar.

Stanton said the drone has been carrying out surveillance missions for American and Canadian law enforcement agencies during its test run in upstate New York.

In assessing whether it could be deployed more widely along the 4,000-mile northern border, officials will look at how many days it could fly in the Northeast’s weather, how many hours it logged and how many mission requests it fulfilled.

The CBP owns seven Predators. Three are based in Arizona and patrol the U.S.-Mexican border. Two others are in California and being converted for marine surveillance. The CBP estimates 18 unmanned aircraft could adequately cover the nation’s southern and northern borders, Stanton said.

The plan to use the drones is a holdover from the 9/11 Commission Report, which recommended tighter security along borders with Mexico and Canada. The agency is using other high-tech equipment, including a network of video cameras and camouflaged ground sensors that detect heat, motion and metal.

The area the Predator has been watching includes the St. Regis Mohawk Reservation, which straddles the U.S.-Canadian border near Massena and is sliced in two by the St. Lawrence River. Its location has made the reservation a gateway for smugglers at least since Prohibition.

Last fall, federal authorities carried out two large-scale busts of drug smugglers operating through St. Regis, arresting 63 people in the sweeps. Investigators said one ring made as much as $45 million smuggling 11 tons of marijuana into the eastern U.S. between 2005 and 2008.

While arrests and drug seizures last year totaled less than 1 percent of those down south, a U.S. Customs and Border Protection report to Congress last year noted a “significant concern” that extremists could slip across the northern border.

WILLIAM KATES