Should I visit the USA embassy or Immigration first for a damaged passport due to washing machine incident?

I hope this post is okay here, My passport went through the washing machine and could be considered damaged, although no damage to the ID page and all the stamps, visa and extensions can still be read. My question is do I go to the USA embassy first or should I go to Immigration first? I read the embassy may not give it back to me and shred it. If that, than what? Thanks in advance.