It is the first time the euro has been set as the default currency in any Rosneft oil product tender and reflects Rosneft's attempts to offset any possible negative impact of US sanctions Russia on the company's business, three traders said.

"The default payment currency should be euro," the tender document published on Rosneft's website showed. For years, Rosneft used US dollars as the default currency in contracts.

Rosneft said in the document it may consider accepting payment in US dollars or Russian roubles as well, but such a payment should be made 'only upon mutual agreement between the parties'.