(Reuters) - The mother of a 2-year-old boy who died after falling into a pit of African wild dogs at the Pittsburgh Zoo stood him up on a railing before he fell and was immediately attacked by 11 dogs, police said.

The boy was visiting the zoo with his 34-year-old mother, who had put him on the railing for a better view of the animals, known as African painted dogs, police said.

The zoo was closed immediately after the incident on Sunday and remained shut on Monday.

Authorities are trying to determine if the boy died from the fall or the attack, Pittsburgh police spokeswoman Diane Richard said on Monday.

Eleven dogs swarmed the boy after he fell. Zookeepers rushed to the exhibit area housing the animals, firing darts to frighten them away from the child before police arrived.

Zoo staff secured 10 of the dogs but police entered the pit and fired multiple gunshots to kill the last dog, which was particularly aggressive toward the child and the officers, authorities said.

African painted dogs are endangered and native to sub-Saharan Africa, according to the National Geographic website.

The animals have an average size of just over 2 feet to 3.5 feet (0.6 meters to 1 meter). They are also known as Cape hunting dogs or painted dogs because of their mottled coats with patches of red, black, brown, white and yellow fur. (Reporting by Kevin Gray in Miami; Editing by Bill Trott)