The Islamic State on Wednesday took over Tora Bora, which once served as Osama Bin Laden's mountain hideout in eastern Afghanistan, from Taliban fighters, according to Afghan officials and local elders.
The tunnels of Tora Bora were built by the Taliban with the USA help during the Soviet-Afghan war (1979-89), and later served as an Al Qaeda and the Taliban stronghold during the 2001 USA invasion.
Abu Omar Khorasani, an ISIS commander in Afghanistan, said that his fighters had seized Tora Bora and were fighting Afghan government and United States forces. There has been no comment from IS or the Taliban so far.
According to testimony from al Qaeda captives in the USA prison at Guantamo Bay, Cuba, bin Laden fled from Tora Bora first to Afghanistan's northeastern Kunar province, before crossing the border into Pakistan.
Visiting the troops on the frontline in the Chaparhar district close to strategic Tora Bora, Gen. Mohammad Zaman, commander of the Afghan National Army's 201st Silab Corps, said that around 700 militants of the terror group were killed in the past three months alone during ongoing Hamza operations.
Tora Bora, which is located in Afghanistan's Nangarhar province, was Osama bin Laden's hideout until December 2001, when he narrowly escaped a botched USA bombing campaign.
First emerging in 2015, I.S.'s local affiliate has made steady inroads into Afghanistan, overrunning large parts of Nangarhar and Kunar provinces and challenging the bigger Taliban militant movement on their own turf.
Pakistan complained the raid violated its sovereignty while bin Laden's presence - barely a few miles from the Pakistani equivalent of America's West Point military academy - reinforced allegations by those who accused Pakistan of harboring the Taliban and al-Qaeda militants. He later crossed into neighboring Pakistan, where he was killed in a US raid in 2011.
"We are in Tora Bora but this is not the end", Khorasani said.
In the Tora Bora area, residents were angry at both the Taliban and the government for allowing the Islamic State to take over.
The growing influence of Islamic State in the country has been a cause of worry for officials for quite some time now amid an already deteriorating security situation and as the state is still fighting Taliban insurgency in some regions.
Around 800 fighters for the so-called caliphate are understood to have moved into Afghanistan.
In August 2016, ISIS-K and the Taliban had reportedly forged a tenuous truce, promising to fight only the US-backed forces.