"If there are sufficient grounds, we do not rule out" new sanctions on Iran, the official, who asked to remain anonymous, told journalists.
But he added Moscow wanted first to see evidence from the International Atomic Energy Agency on the latest status of Tehran's nuclear program.
Western nations suspect Iran is trying to develop a nuclear bomb, something Tehran has denied saying its nuclear program is for civilian purposes only.
"The criteria for us is not from some kind of individual estimate, but reports and recommendations from the International Atomic (Energy) Agency."
He added that Moscow "does not rule out participating in developing new decisions by the Security Council on issues of sanctions."
Earlier, a top Russian diplomat told AFP that Russia would keep working for a political solution on Iran ahead of fresh international talks planned for October 1.
"In our opinion, today the question should not be 'sanctions or not sanctions,' but how to find a political solution to end this problem," said Sergei Kislyak, the Russian ambassador to the United States and former negotiator on Iranian nuclear issues.
"There is a chance for that and we will work at it," he told AFP.
"Today the priority is to start a serious dialogue with the Iranian partners on how to resolve this situation," said Kislyak, Russia's former deputy foreign minister.
Chief diplomats of the United States, Russia, China, Britain and France as well as Germany were to meet here later Wednesday to prepare for the key talks with Iran in Geneva next week.
They hope to reconcile the aims of the United States and Europe — which seek new sanctions if Iran continues to enrich uranium — with the more cautious attitude from Russia and China.
