BOISE -- Bad dog!

The number of postal carriers bitten by dogs in southern Idaho more than doubled last year, the United States Postal Service said.

In 2016, a total of 30 carriers were bit, up from 14 the year before.

Most of the incidents were more than nips, the Postal Service says: A majority of the workers bitten needed medical care beyond first-aid, and were unable to return to their normal duties for some time.

USPS District Manager Darrell Stoke said pet owners need to be more careful about maing sure their dogs are secured.

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"Behind these statistics are real people suffering real pain and injuries that, depending on the situation, can be life threatening,” Stoke said. “We strongly encourage dog owners to restrain their dogs and allow the carriers to deliver the mail safely. We take the safety of our employees very seriously. We will not wait until a carrier is bitten before taking preventative action. A dog that runs loose not only affects the delivery of the dog owner’s mail, but often the delivery of their neighbors’ mail as well.”

Boise had the most dog bites to postal workers, with nine bites in 2016. Idaho Falls followed with eight bites.

In one of last year's dog attacks, a postal was bitten after a dog ran out of the house as the owner opened the front door to take a package. The employee needed stitches to close the wound, the postal service says.

USPS warned that anyone whose dog bites a postal worker will be held liable for the person's medical expense and other costs, which can add up quickly.

The postal service urges people to help keep mail carriers safe by keeping dogs from roaming the neighborhood, and securing them in another room before opening the door to accept a package or certified letter. Children should also be reminded not to take mail directly from the carrier, which some dogs interpret as a threat, the USPS says.