Two halides in solution that I have to identify?

I have a solution, A, in which there are two halides. I have to identify them. When I add silver nitrate, the solution turns whitish/creamy, and I don't know if this would indicate Chlorine or Bromine. When I add concentrated ammonia, a dark/brown precipitate (a very small amount) appears in the solution. Adding nitric acid didn't result in any visible change. Any ideas which two halides are in solution A? Thanks in advance.