Iraq said on Saturday that its military officials were engaged in intelligence and security cooperation in Baghdad with Russia, Iran and Syria to counter threats from Islamic State extremists, a pact that could raise concerns in Washington.

A statement from the Iraqi military's joint operations command said the cooperation had come because of "increased Russian concern about the presence of thousands of terrorists from Russia undertaking criminal acts with Daesh" - an alternate name for IS.

The move could give Moscow more sway in the Middle East. It has stepped up its military involvement in Syria in recent weeks while pressing for Damascus to be included in international efforts to fight Islamic State, a demand the United States rejects, Reuters said.