A volunteer at a North Haven animal shelter is recovering after being mauled by a dog, according to the shelter.

It happened at The Animal Haven on Wednesday, the shelter said in a statement.

According to the shelter, it happened as the volunteer opened the door to the room where the dog, named Sarge, was being held.

“Without provocation, Sarge jumped at the volunteer before she could even enter the room and savagely mauled her face,” The Animal Haven said in the statement.

The volunteer survived the attack, but was seriously injured and has since undergone reconstructive surgery, they said.

The operators of the shelter say Sarge is a big, strong dog, but has never shown aggression while at the shelter. They said the volunteer was familiar to the dog and visited him regularly.

Sarge was vaccinated for rabies when he arrived at the shelter, but operators say they can’t rule out that the change in his behavior was caused by rabies and that he may have been infected prior to receiving his vaccination.

It was initially suggested that the shelter euthanize the dog so that he could be tested for rabies, but the victim is now being treated for rabies as a precaution, so there is no immediate need to euthanize the dog, according to The Animal Haven.

Sarge will now be quarantined for at least 10 days to see if he shows symptoms of rabies.

After the quarantine, The Animal Haven says it will look for another facility that will accept Sarge and is better equipped to handle him.