Using the savedmodel in this project for transfer learning in Keras

I've my own dataset that I want to train upon and want to use the bottle-neck layer in the saved model. The problem is that I want to do it in Keras but the savemodel seems to be saved in .pb and .ckpt files. I would appreciate if you can guide me towards transfer learning in tf 2.0 or how to convert the .pb and .ckpt files to generate a Keras model?