KABUL—Taliban fighters killed dozens of government soldiers in overnight attacks on two security checkpoints in northwestern Afghanistan, authorities and medical personnel said Wednesday, in the insurgent group’s first major assault since refusing to extend an unprecedented three-day cease-fire.
Hundreds of militants launched the coordinated assault on the guard posts in Badghis province, on Afghanistan’s border with Turkmenistan, early Wednesday, then ambushed two armored vehicles sent to aid the troops during the four-hour...