PEMBINA - Along the expansive Canadian border, a lack of agents and antiquated motion sensors can make it difficult to distinguish between a would-be terrorist and a wayward moose, officials say.

Law enforcement officials and lawmakers argue more funding is needed to put more agents and reliable technology along the 4,000-mile border. Without both, it's impossible to hunt down everything that trips the sensors or know who - and what - is trying to get in.

"It's pretty much a joke," said Towner County Sheriff Vaughn Klier, whose territory stretches to the border.

Officials won't say how many of the motion detectors are buried along the border, citing security concerns. But U.S. Border Patrol supervisor Brent Zimmerman said he doesn't entirely trust the sensors, because they're difficult to maintain and rely on batteries.

Michelle Bacon, an assistant patrol agent in the North Dakota and Minnesota sector, said many of the sensors are outdated and susceptible to their surroundings.

"With our weather and stuff, we can't always count on them in the winter or when it's pouring rain," Bacon said.

Replacing the sensors with a more refined, easier to operate system would help, but that's not likely to happen soon, said Rep. Earl Pomeroy, D-N.D.

"The technology that is going to take us where we need to go is still either under development or hasn't been funded," he said.

There were 6,599 arrests on the northern border in 2006, including 518 in the Minnesota and North Dakota sector. That compares to more than 1 million arrests on the Mexican border.

Scott Baker, the Border Patrol chief for the North Dakota and Minnesota sector, said his agents have an added challenge because problems are not as obvious as they are along the more populated southern border.

Pomeroy said he believes Congress has spent too much time trying to make passports mandatory and not enough time figuring out a way to increase the number of Border Patrol agents.

"If you're a terrorist, you're not waiting in the long line to talk to the Customs guy," he said.

Klier said no matter how good the equipment works, there's not enough manpower in the Border Patrol or local police forces to monitor the U.S.-Canadian line - whether the sensors are tripped or not.

Staff and technology resources have tripled along the northern border since the Sept. 11 attacks, Border Patrol spokesman Lonny Schweitzer said, though he would not give specific numbers, again citing security.

Congress recently added $50 million to the Border Patrol's budget, and the agency will add 3,000 agents to its ranks, Pomeroy said. "We're going to get a few of those," he said.

Zimmerman is curious about the promise of new technology, including unmanned aerial vehicles, but the Border Patrol veteran still believes the most important defense against terrorists, drug smugglers and illegal immigrants is people, including civilians.

"We rely mercilessly on the public," he said.

The solution also means checking everything from hotel registries to grain bins and railway cars, Zimmerman said.

"If you're hardcore about getting into this country, you're going to find a remote place," he said.