Son won’t poop in the potty

My son just turned three and we started potty training this week. Pee has been going great, but he will absolutely not poop in the potty. He knows when he has to go, because he’s been telling me for a while when he has to, and he understands poop goes in the potty, but he will absolutely not do it there.

He stopped telling me when he has to go, because he knows if he tells me I will put him on the toilet, so now he goes somewhere privately and goes in his pants.

I caught him in the middle of it, and I brought him to the toilet, and he flipped out, screaming crying, jumping off the potty. He is legitimately scared to go.

I tried offering him privacy, I put him on there, and walked out and stood by the door, but he jumped off.

I really don’t know what to do. He doesn’t tell me when he has to go anymore, so that is not helping.

Has anyone had a toddler who was afraid to go in the potty? Any tips?