Los Angeles, California - When Pancho the dog was released from the shelter, it was supposed to be his first step into a new life, but the 5-month-old puppy refused to leave his best friend behind.

The touching scene was shared on the animal shelter Let's Rescue Dogs' Instagram page, melting countless hearts.

Pancho, who was being taken in by a foster family, kept looking sadly back at the shelter and whimpering softly.

The dog's gaze radiated longing because his beloved sister Pancha was still inside.

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Pancho and Pancha had been surrendered together by their previous owners.

The staff at the shelter knew one thing right away: these two dogs belonged together, forever.

"I've never seen a pair of shelter dogs more bonded than them," the shelter wrote in an Instagram post.

"Pancho cried and refused to go to the car until he saw that we were not leaving his sister behind."

The sweet video showing the dogs being reunited went viral online and attracted tens of thousands of viewers.

The moment the dog siblings meet again, the air explodes with emotion: wagging tails, leaps of joy, and lots of loving licks. Aw!