Older child hitting baby

I have 2 children, a 2.5 year old and a new baby who is 4 weeks. The older one can be really nice and gentle but has also started hitting the baby. At times, she'll rock her moses basket knowing that the baby can fall out. I obviously stop her or take the baby out to avoid the worst happening. The older one also claws at the face of the baby - lashing out with intent to hurt her.

I find it really upsetting because I don't want to be getting angry at the older one who I think just wants attention (which she does get a lot of) but also because it means she wants to hurt thre baby. I know she's young so doesn't understand consequences fully but I don't know what to do.

Any advice on how to get older one to be more accepting and gentle with the baby? I'd love to be in the position of being able to leave them in the room together, which I absolutely can't do at the moment.

Thanks