Handling two female puppies

Question
we have two female sibling puppies.They are of three months.till the date they they were really friendly and loving with each other but from today onwards they have started fighting with each other so dangerously, that its a big matter to worry. pl. reply asap.

Answer
These puppies cannot live together; one of them must be re-homed.  Keeping two of the same sex (or even of opposite sex) from the same litter is always risky.  Temperament is often so similar that it's impossible for the puppies to establish normal pecking order.  Find a good home for one of these puppies ASAP and, until then, keep house tab (leash with handle cut off) on both and separate them immediately when there's a problem (by taking the aggressor's leash and leading it elsewhere).  Do NOT leave them alone together.  It's possible you have contributed (unintended) to this problem but, again, I can't see anything from here.  The best approach is the most conservative: re-homing one to a good, loving home is the answer.