BEIRUT, LEBANON (REUTERS) - The hardline Islamic State group called on Muslims to launch a "holy war" against Russians and Americans over what it called their "crusaders' war" in the Middle East, according to an audio message distributed by their supporters on Tuesday.

"Islamic youth everywhere, ignite jihad against the Russians and the Americans in their crusaders' war against Muslims," the speech by Islamic State spokesman Abu Mohammad al-Adnani said.

The United States and Russia are carrying out airstrikes in Syria, which they say are targeting Islamic State.