Packs of Chihuahuas are scaring children and others in Phoenix, Ariz., according to an animal facility there and multiple media reports.

The packs consist of up to 12 Chihuahuas -- and they're not usually happy.

"Yeah a lot of them they are out here chasing kids or going yard to yard ... anywhere in groups of eight to twelve just running around," Ray Rios, a resident of Phoenix's Maryvale neighborhood, told the local Fox affiliate there.

Photos: Ugliest Dog Contenders

Another resident, Frank Garcia, told Fox, "Well the last time I seen six or seven Chihuahuas… and big dogs running with the Chihuahua's in a pack running every single day."

Even though the dogs are tiny, most people would likely be startled to see multiple Chihuahuas come yapping and running toward them, and not in a friendly manner. It’s no wonder kids are chased away.

Maricopa County Animal Care and Control reported that in 2013, it received 6,000 calls for service from Maryvale residents who were bothered by Chihuahuas and other dogs running loose. Who let the dogs out? Apparently a lot of people in Phoenix did.

Maricopa County Animal Control spokesperson Melissa Gable said that "obviously you have the deal with feces and (it) is unsanitary and all these strays everyone is at risk for dog bites."

Photos: Dogs In Combat

"Part of it is these animals aren’t spayed or neutered, so they're out looking for a mate and are having babies, which also contributes to the problem," Gable told ABC News, adding that residents are encouraged to call Animal Control if they see the stray dogs.

The facility is now neutering male Chihuahuas for free in response to the problem.

The history of these tiny dogs is somewhat of a mystery, although canine experts suspect Chihuahuas are descended from a small dog known to Mexico's Toltec civilization. Socialized dogs make fantastic pets, but without proper care and training, the dogs can be easily provoked.

The British Chihuahua Club notes that Chihuahuas also can be "clannish," preferring the company of other Chihuahuas or Chihuahua mixes.

Photos: The Earliest Dogs

If you happen to visit Phoenix then, watch out for the Chihuahua gangs there and perhaps consider adopting one. They are fiercely loyal to their humans and will yap like an alarm when intruders are around. Because they are small, their barks usually aren't loud enough to disturb neighbors, but they will alert you.

Photo: Douglas Muth, Flickr