How can I stop my 3 year old daughters fighting?

My 3 year old twin daughters are beginning to fight between each other. I don't mean the occasional bickering but in the last few days they have been really violent towards each other, I'm talking kicking, punching exc. which resulted in a blood nose just this morning. I cannot move them into seperate bedrooms because we have no more bedrooms so thats not an option. Any suggestions to help fix this problem would be great, thanks. I knew this would happen eventually as siblings do fight between each other but I wasn't expecting it so soon!