The Latest: 2 US troops, 2 US civilians dead in Syria blast

BEIRUT (AP) — The Latest on developments in Syria (all times local):
10:20 p.m.
Two U.S. soldiers and two American citizens were among those killed Wednesday in a suicide bombing in northern Syria.
U.S. Central Command says one of the civilians was employed by the Defense Department and the other was a contractor. The names of the American victims were being withheld until their families are notified.
The Islamic State claimed responsibility for the explosion.
The attack, which observers s