Justin Bieber Blasts PETA for Criticizing His Exotic Cat Purchase

Justin Bieber's not playing with PETA -- he's firing back hard at the animal rights org after it slammed him for dropping $35k on 2 exotic cats ... telling them to suck it.

JB adopted a pair of Savannah kittens a little more than a month ago -- which he named Sushi and Tuna -- and revealed the brother and sister felines on Instagram as "my children" ... much to the dismay of PETA.

It released a statement chastising his exotic pets purchase, grousing he should have adopted cats from a local shelter. Justin caught wind of the criticism ... and went off.

In a series of IG Stories, Bieber first posted a screenshot of an article about the backlash but added his own caption -- "PETA can suck it."

He then went on to blast the org for going after his new cats instead of focusing on real problems -- "Like poaching, and animal brutality." Bieber says he supports adopting rescues but also believes it's fine for people to go to breeders when they have preferences for their animals.

Finally, he tells PETA to "go help with all of the plastic in the ocean" and leave him -- and his cats -- alone. Of course, he then plugged the kitties' own Instagram page.

PETA President Ingrid Newkirk has responded to Bieber already, urging him to think more about the issue and spend one hour in an animal shelter with the org.

She says ... "When millions of animals are losing their lives every year because not enough people adopt—choosing instead to shop—the animal overpopulation crisis is a 'real problem.' That's what 'sucks'."