The cubs were born on Nov. 13 to parents Reka, 5, and Maxim, 11.
"The Animal Care Team has worked hard to support Reka throughout this journey, from introductions to Maxim to the birth of the cubs. It is incredibly rewarding to see her be such a gentle and attentive mom," said Julie Hartell-DeNardo and Kevin Beckmann, curators of carnivores at the Saint Louis Zoo.
Reka and her cubs are resting comfortably in their private maternity den and will stay there for the next few months, according to a zoo news release.
Reka and her newborn cubs. (Jackie Voelkel/Saint Louis Zoo)
"The first few months of life are critical for newborn tigers. The Animal Care team is monitoring the tigers via camera and has observed Reka being an attentive mom, cleaning, feeding the cubs and keeping them warm," the news release continued.
Amur tigers are one of the most endangered big cats in the world, according to the zoo.
There are less than 500 Amur tigers left in the wild and many of them live in Russia. This species is at high risk of extinction due to habitat loss, poaching and human-wildlife conflict.
The birth of these three cubs is a significant contribution to the population of Amur tigers in captivity, the zoo said.
This story was reported from Los Angeles.