Russia has special responsibility to push Syria to stop attacks - U.S.

WASHINGTON (Reuters) - The United States said it was not discussing joint air strikes with Russia on Monday and called on Moscow to press Syrian President Bashar al-Assad's government to cease air strikes against opposition forces in Aleppo and the Damascus suburbs.

"We're not looking at joint operations," said State Department spokesman Mark Toner. "We're discussing with them proposals for sustainable mechanisms to better monitor and enforce the cessation of hostilities - we're not talking about joint operations."