Salary negotiation

In my opinion, after going through so many interviews in my career....if you had already indicated your expected salary, then you should be honest with the HR and tell them that is what you are expecting. And you may also ask nicely what do they mean by negotiate? Is it negotiate lower (which is what they are trying for). So that they can then rank you with other candidates. Then you need to take a stand for yourself for what you see your value as.

Usually a good sign meaning that you’re being considered as a serious candidate.

Negotiate using your annual package instead of monthly. You can assume 12 months salary with 2 months bonus. And ask for 5-10% increment on your annual which would work out to a ~25% increase in your current monthly.

Simple math to illustrate,
$100 current monthly 14 months 5% increment / 12 months = $122.5 new monthly salary