News Analysis: Officials Eye Euphrates River Valley as Last Stand for ISIS

Even with the Islamic State on the run, U.S. advisers grapple with political and military problems in wresting Iraqi and Syrian towns from extremists.

Under Trump, a Hollowed-Out Force in Syria Quickly Lost C.I.A. Backing

The shuttering of the C.I.A. program, one of the most expensive efforts to arm and train rebels since the 1980s, has forced a reckoning over its successes and failures.

Commando Raids on ISIS Yield Vital Data in Shadowy War

Risky Special Operations missions targeting midlevel figures can prove valuable for unearthing information about the Islamic State’s inner circle.

U.S. Says It Shot Down Drone That Attacked Fighters in Syria

The drone had dropped a munition near Syrian fighters who were accompanied by advisers from the American-led coalition, the United States military said.

Mattis Says Escalation Against ISIS Doesn’t Imperil More Civilians

Defense Secretary Jim Mattis said President Trump’s decision to give the military more latitude had put greater pressure on militants in Syria, Yemen and Somalia.