U.S. Warns Russia It Will Hit Assad If He Uses Chemical Arms, Sources Say

The U.S. and Russia exchanged warnings about a possible chemical attack in Syria and a Western military intervention in response, on the eve of what may be one of the most decisive campaigns in the Middle Eastern country’s civil war.

Tensions between the nuclear powers flared after National Security Adviser John Bolton told his Russian counterpart, Nikolai Patrushev, that the U.S. has information Syrian President Bashar al-Assad may be preparing to use chemical weapons to recapture the northwestern province of Idlib from rebels.