[This](https://www.theguardian.com/uk-news/2018/mar/18/vladimir-putin-nonsense-to-think-russia-would-poison-spy-in-uk) article from The Guardian features a quote from Putin claiming that Russia destroyed all their chemical weapons:

> 
> “Secondly, Russia does not have such [nerve] agents. We destroyed all
>  our chemical weapons under the supervision of international
>  organisations and we did it first, unlike some of our partners who
>  promised to do it, but unfortunately did not keep their promises.”
> 
> 
> 

However, I was unable to confirm or refute this claim as it is not mentioned when or with whom Russia cooperated for this.