Islamic State have reportedly moved to take control of a former stronghold of Osama Bin Laden.
Officials in Afghanistan say the terror group has seized territory around Tora Bora, a giant cave hideout used by the former Al-Qaeda leader.
Militants began their assault late on Tuesday night, and fighting with the Taliban and local villagers continued into the day on Wednesday.
It appears as though the attack was eventually repelled, but officials said land surrounding the cave network had been taken by Isis.
It is claimed they placed heavy artillery placements on the hilltops around Tora Bora.
Isis have come under attack from numerous fronts in recent months - notably in the de-facto capital of their caliphate, Raqqa, which is being subjected to a siege by the Syrian Democratic Forces.