Russian Deputy Foreign Minister Sergei Ryabkov said on Wednesday that a trove of U.S. intelligence documents posted online in recent weeks might be fake and a deliberate attempt to mislead Moscow.

The documents, the authenticity of which Reuters has not been able to independently verify, include what look like classified U.S. assessments of the war in Ukraine and the casualties purportedly suffered by the two armies, as well as documents covering other countries.

Ryabkov told Russian news agencies on Wednesday that, for now, the leak threw up many questions.

"It's probably interesting for someone to look at these documents, if they are documents at all, or maybe they are fake, maybe this is a deliberate information dump," Ryabkov was cited as saying.

"Since the United States is a party to the (Ukraine) conflict and is in essence waging a hybrid war against us, it's possible such things are being done to mislead the enemy - that is the Russian Federation," he said.

The Kremlin said earlier on Wednesday that it did not know "like everyone else" how authentic the documents were.

Some national security experts and U.S. officials say they suspect that the leaker could be American, but do not rule out pro-Russian actors.

A former CIA officer has said it is highly likely that Moscow orchestrated the leak in order to sow confusion and potential divisions between Washington and its allies.

When asked about such allegations, the Kremlin has said there's a tendency to always blame everything on Russia.