Wave after wave of Mexican drug and immigrant smugglers are crossing into the U.S., passing through the Arizona border where nearby ranchers say they feel unprotected by their own government. NBC's Mark Potter reports.

By Mark Potter, NBC News correspondent

ARIVACA, Ariz. -- Just before nightfall, 73-year-old rancher Jim Chilton hikes quickly up and down the hills on his rugged cattle-grazing land south of Tucson, escorting two U.S. Border Patrol agents.

He wants to show them the disturbing discovery he made earlier in the day: a drug-smugglers' camp on his private property. Stacked together under a stand of trees are blankets, jackets, food, water, binoculars and bales of marijuana from Mexico wrapped in burlap. The smugglers, themselves, are nowhere in sight and are believed to have fled the area, which is about 10 miles north of the Mexican border.

Rancher Jim Chilton shows what's left of a drug smugglers camp on his ranch.

"The druggers outrageously use my land at will," said Chilton, who frequently finds evidence of smugglers on his land -- well-worn trails, cut fences, discarded water bottles, clothing and shoes. His home has been burglarized twice and he is constantly on the lookout for armed smuggling groups while he and his employees round up cows on his remote land.

"Can you imagine riding your horse through here on your own land and running into a guy with an AK-47 and 20 or 30 guys behind him dressed in camouflage and carrying drugs?," he asked.

Hidden cameras in southern Arizona captured footage of armed drug smugglers in 2012.

Like living ‘in a no-man’s land’

The land where Chilton raises his cattle covers 50,000 acres south of the small town of Arivaca, Ariz. About five miles of his property runs along the international border, where all that separates Mexico from the United States in most areas there is a four-strand barbed-wire fence. Chilton owns some of the land outright, but leases most it from the state and federal governments for cattle grazing.

Mark Potter / NBC News Ranchers Jim and Sue Chilton in Arivaca, Ariz., say drug smugglers use their land frequently, and their home has been burglarized twice.

He and his wife, Sue Chilton, complain they feel caught in the middle between the Mexican drug and immigrant smugglers and the United States Border Patrol, which the Chiltons and other ranchers accuse of concentrating most of its patrols and checkpoints miles north of the border, far beyond where the ranchers live and work.

"It's like living in a no-man's land. The Border Patrol doesn't really protect us, they try to arrest people north of us," said Chilton. "I think the druggers should be stopped at the United States border. They shouldn't be allowed into this country. The Border Patrol should secure the border at the border."

Ranchers Jim and Sue Chilton live on the U.S.-Mexico border where drug smugglers constantly walk across their property.

Jeffrey Self, who heads the U.S. Customs and Border Protection joint field command in Arizona, said it is not fair to characterize the area as a "no-man's land." He conceded, though, that Arizona ranchers are correct when they report Mexican drug and immigrant smugglers crossing their land.

"Yes, there is traffic out on those ranch lands. Communities continue to be impacted to a certain extent,” he said. “But you can't discount the fact that gains have been made over the course of the last few years.”

Jeffrey Self, head of the U.S. Customs and Border Protection joint field command in Arizona, says a lot of gains have been made at border protection, but acknowledges more is needed.

With 5,500 Border Patrol agents assigned to Arizona, double the amount stationed there in 2004, Self argued that much more territory is being patrolled now than in the past. And he said daily surveillance flights and advances in camera and sensor technology have also helped dramatically reduce the number of illegal border crossings.

"If you look back to 2000…there were 610,000 aliens arrested in Arizona,’ Self said. “Just look at last year, we came in at 119,000."

Over the past decade, however, there has been a dramatic rise in the amount of illegal drugs smuggled from Mexico into Arizona. The Border Patrol there seized about one million pounds of marijuana during each of the last several years -- about four times the amount seized in 2000. Other illicit drugs, such as heroin and meth, are also entering Arizona in greater quantities than ever before.

‘He came out screaming’

For neighboring rancher David Beckham the problem is even more severe. Earlier this year he made the painful decision to move himself, his wife and three boys away from their ranch, which sits about 12 miles north of the Mexican border.

Arizona rancher David Beckham says drug smugglers crossing his land forced him to move his family.

"It's not safe, it’s not safe for my kids," he said. The Beckhams have had numerous run-ins on their land with Mexican smugglers.

Their cattle fences are frequently cut and paths heading north from Mexico cross their property. Beckham says a smuggler even fired shots at him while he walked his land with a U.S. Border Patrol agent. Several illegal border crossers have also approached his house at night--one even reaching his hand into their bathroom window.

"Several years ago, one of my children was taking a shower and had a gentleman reach into the shower while he was in there, and he came out screaming, absolutely refusing to take a shower for the next couple months."

The Beckhams, like the Chiltons, scoff at the Obama administration’s claims the U.S.-Mexican border is safer than ever.

"It's a joke, they can believe what they want. They can live in candy land," said Beckham. "You can't have a safe and secure country without a safe and secure border, and we don't have it. We don't."

Sue Chilton says she believes a U.S. government decision to not to heavily patrol right along the border is, in effect, creating a free-access zone for Mexican smugglers.

"We have, without any reason or logic to it, decided to cede as much as 15 or 20 miles of the United States to the cartels, and we live in that section that has been ceded," she said. "They have lookouts in the mountains within a mile of our house."

Several advocacy groups concerned about border security have placed motion-activated hidden cameras near the Chilton's ranch and elsewhere in southern Arizona. Their videos, many of them shot recently, confirm the ranchers' complaints, revealing wave after wave of drug and immigrant smuggling groups, sometimes heavily armed, crossing U.S. land miles north of the Mexican border.

"First, it's a threat to our life," said Chilton. "Second, it's a threat to our livelihood."

Border Patrol: agents more thorough than ever

As to the complaint the Border Patrol places most of its patrols and checkpoints miles north of the border fence, Jeffrey Self of the Customs and Border Protection’s joint field command in Arizona said agents are assigned where they will be most effective in apprehending smugglers and illegal immigrants.

"I would get less out of putting those agents on the line than having them operate those checkpoints," He said.

Still, many agents do patrol the border fence, he said, and are "in and around those ranchers every day, 365 days a year." Serious problems stemming from distance and budgets, however, do hamper some daily Border Patrol operations. Agents stationed in Tucson have to drive as many as two hours a day just to reach parts of the remote and rugged border. And a spokesperson confirmed that a Border Patrol FOB (Forward Operating Base), built west of the Chilton ranch, is currently unmanned because there isn't enough money to pay agents' overtime fees. The FOB was built to house agents day and night right at the border near Sasabe, Ariz., and to reduce the current drive times.

Nevertheless, Self said, his agents are doing a better, more thorough job than ever.

"Is there still traffic coming across [ranchers’] property? Absolutely. Do we want them to feel safe in their homes? Absolutely. We're going to work toward that effort."

Drug smugglers move through Arizona in this footage captured by hidden cameras in 2012.

Ranchers describe smugglers as ‘desperate’

The Chiltons, Beckhams and other ranchers in southern Arizona give high marks to the Border Patrol agents, themselves, respecting the dangerous work they do and appreciating their willingness to help property owners in need.

The complaint they have is with where those agents are assigned. The ranchers also believe, as do many of the agents, themselves, that smugglers crossing the border now are more heavily armed and confrontational than in years past.

"They seem to be a lot more desperate. The people coming across now are different, they are not friendly," said Beckham.

Surveying her ranchland, Sue Chilton described what happens when smugglers walk close to their house at night: "We turn out the lights, Jim gets his guns and we sit somewhere in the dark in the middle of the house where we are not close to our window and wait for the action to be finished."

Her husband, Jim, who comes from several generations of ranchers, said he has never seen the border as dangerous as it is now.

"It's outrageous. I'm a citizen of the United States. I expect to be protected like everybody else," he said. "The border is not secure, it is worse than it's ever been."