ISIS tunnels under al-Bab point to hard fighting ahead
AL-BAB -- Syrian rebels who drove Islamic State from the town of al-Bab in northwest Syria this year discovered an extensive network of tunnels dug by militants as part of their defences, a tactic that has slowed the military campaign against them.
"The tunnels complicated the fighting a lot and stopped our advance for weeks," said Mohammed Abu Yousef, a rebel in a group fighting under the banner of the Free Syrian Army as part of a Turkey-backed military campaign in north Syria.
