A Texas sheriff claims that immigrants who cross the border into the country illegally are armed and walking around his county "in military fatigues," according to the Daily Mail.

Willacy County Sheriff Larry Spence said local farmers have spotted groups of undocumented immigrants, some armed, wearing military fatigues and marching single file throughout ranches located some 25 miles north of the U.S.-Mexico border.

One sighting allegedly took place about four months ago.

"We had an individual who saw people walking through farm property in military fatigues, with backpacks," Spence told the Daily Mail. "He went out and asked them 'who are you,' they said 'what's it to you,' he said he owned the property and they said, 'well you better get out of here.' "

"Sensibly he left and called us, but by the time we got out there, they were gone," the sheriff said.

Spence's comments come a day after the Border Patrol Council named two undocumented Mexican immigrants accused of murdering an off-duty border patrol agent in Texas.

Gustavo Tijerina and Ismael Hernandez have been charged with the shooting death of Border Patrol Agent Javier Vega last Sunday while he was on a fishing trip with his family in Santa Monica, NBC News reported. Both suspects have been deported from the U.S. more than once, border patrol officials told the station.

Spence's department handled the investigation into Vega's death. He said the current border crisis, marked by thousands of adults and unaccompanied children coming into the country from Central America, is getting worse.

While the focus has been on the humanitarian element of the spike in immigrants, they are bringing in drugs and committing crimes, which the U.S. government is ignoring, according to the sheriff.

"We as Sheriffs have the trust of the people, especially near the border. If we don't stop it here, then the problem is going to spread." Spence told the Daily Mail. "We need to help come up with a solution."