Very cute kittens!
My guess is that they’re the offspring of a stray or feral mama. Not sure from looking at them how old they might be, but if they’re 8 weeks or older, they’re old enough to be separated from their mama and adopted out (ideally together). Try contacting Homeward Trails — http://www.homewardtrails.org/ — or another rescue group and see what they recommend.
If you’re willing to foster the kittens, HT can list them on their website and can vet potential adopters. And if you want to adopt them yourself, HT can likely advise on how to proceed.