Afghan civil war 'likely': top US general

Afghanistan will "likely" erupt in civil war, the top US general told US media Saturday, warning that those conditions could see a resurgence of terrorist groups in the country.

As American forces began their withdrawal, the Taliban took over Afghanistan in a lightning campaign, with only the northern province Panjshir holding out against the hardline Islamists.

"My military estimate... is that the conditions are likely to develop of a civil war," General Mark Milley, chairman of the Joint Chiefs of Staff, told Fox News.

He questioned whether the Taliban -- who are yet to declare a government -- would be able to consolidate power and establish effective governance.

Read more: Taliban, opposition fight for Afghan holdout province

"I think there's at least a very good probability of a broader civil war and that will then in turn lead to conditions that could, in fact, lead to a reconstitution of Al-Qaeda or a growth of ISIS or other... terrorist groups," Milley said.

Emphasising that he could not predict what would happen next in Afghanistan, he nonetheless gave a bleak assessment.

"The conditions are very likely," Milley told Fox News, "that you could see a resurgence of terrorism coming out of that general region within 12, 24, 36 months."

Also read: Taliban say they have entered capital of holdout Afghan region

The United States invaded Afghanistan and toppled the first Taliban regime in 2001 in the wake of the 9/11 attacks by Al-Qaeda, which had sanctuary in the country.

Western governments fear Afghanistan could again become a haven for extremists bent on attacking them.

The United States has said it will maintain an "over-the-horizon" capability to strike against any threats to its security in Afghanistan.