Peskov said an information centre was being established in Baghdad to share information between Russia, Iran, Iraq and Syria. Russia has also agreed a separate such mechanism with Israel.
Peskov said he had no information of any Russian air strikes taking place against targets in Syria.
He also said ties between Washington and Moscow were still not at their best but expressed willingness to cooperate with the United States on solving acute crises, including in Syria.
Moscow has said the Baghdad centre should become the foundation of a wide international coalition for combating Islamic State.
"It is no secret that American specialists and American military have been invited to work in the Baghdad centre," Peskov told journalists on a conference call.
"Unfortunately, they have not participated in the first meetings and discussions." Separately on Tuesday, Russian state news agency RIA quoted an unnamed source as saying the centre was expected to kick off in October or November.
(Reporting by Darya Korsunskaya; Writing by Gabriela Baczynska; Editing by Lidia Kelly)
