The Kremlin declined on Tuesday to say whether the United States had warned it against sharing intelligence with Iran, as the war in the Middle East entered its 11th day.
The United States and Israel began striking Iran on February 28, prompting a storm of retaliatory Iranian strikes across the Gulf.
The Washington Post reported on Friday that Moscow had passed sensitive intelligence to Tehran, including the locations of US warships and aircraft in the region.
US special envoy Steve Witkoff said Saturday he had "strongly" communicated to Russia not to share targeting information with Tehran.
When asked by AFP about Witkoff's statement, or whether US President Donald Trump and his Russian counterpart Vladimir Putin had discussed this in a phone call on Monday, Kremlin spokesman Dmitry Peskov said:
"All I can say is that Witkoff is in constant contact with his Russian counterparts, and that this channel of communication indeed allows us to hand each other signals about the most sensitive issues."
Trump said Saturday he had no indication Russia was supporting Iran in the war, but that if they were, it was not "helping much".
Russia is a close ally of Iran, with the two agreeing last year to help each other counter "common threats".
