Eligibility to Marry document???

I am an American citizen and plan to marry my fiance in Saint-Petersburg, Russia. He is a Russian citizen.

Where and how can I obtain a document/certification/anything that proves that I am single and have never been married/divorced??? This type of "no marital status" document is required to marry in Russia (and most other countries).

I see that the USA doesn't have this type of document, so what should I do? Is there an alternative option to getting this doc? What have other people done in a similar situation?

Thanks so much!

x-posted in "Pre-Marriage" section