Turkish forces swept into Syria overnight to rescue about 40 soldiers who had been surrounded for months by Islamic State militants while guarding the tomb of a revered Turkish figure.

The Syrian government described the operation as an act of “flagrant aggression” and said it would hold Ankara responsible for its repercussions.

The action, which involved tanks, drones and reconnaissance planes as well as several hundred ground troops, was the first incursion by Turkish troops into Syria since the start of the civil war there nearly four years ago. […]