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The mother of a girl who suffered serious injuries when she was bit in the face last year by a pit bull at a Portland airport has filed a lawsuit claiming the dog's owner did not have it properly contained.

Mirna Gonzalez, of Pasco, Washington, said in her suit filed Monday that she and her family were at Portland International Airport on Dec. 18, 2017, when her daughter, Gabriella, who was 5 years old at the time, was attacked by a dog.

Gonzalez said the dog's owner, Michelle Brannan, said the pit bull was an emotional support animal but faulted her for not having the dog in crate or kennel.

"She went through the ticketing process at Alaska Airlines without the pit bull being in a crate, kennel or other secure container. She then took the pit bull through Port of Portland security without the animal being in a crate, kennel or another secure container," the lawsuit states. "Once inside the secure area of the airport, she went to gate C7 where her pit bull attacked Gabriella Gonzalez."

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The lawsuit alleges that Brannan should have known her dog "was displaying threatening and aggressive behavior and possessed vicious propensities" and bringing the pit bull to the airport put others at risk.

Brannan could not immediately be reached by NBC News for comment.

Gabriella suffered injuries to the muscles, tendons, bone, nerves and soft tissue of her face and eye. She also had to have surgery to repair her tear duct, the lawsuit states. Gabriella's medical expenses have so far amounted to $100,000 and are expected to climb.

Gonzalez is seeking $1.1 million in damages.

The suit also names Alaska Airlines and the Port of Portland, which oversees Portland International Airport, for allowing Brannan to enter the gate waiting area with a dog that "was not a trained and registered service animal" or was not muzzled or restrained.

Alaska Airlines said it was "heartbroken" by what happened to Gabriella and remains "very concerned for our guests’ condition."

A spokesperson for the Port of Portland said they are "refraining from commenting on pending litigation" and referred NBC to its revised rules on passengers bringing animals to the airport which states, in part, that emotional support animals must travel with their owner or be kept in a pet carrier.

If the animal does not fit in a crate, the owner has to either carry the animal or keep it on a leash that does not extend more than three feet from the person's body, the Port of Portland said.