The Taliban says it killed six United States troops in a suicide attack on a military base on Sunday.
The attack underlines the group's ability to hit high-profile targets linked to the US-backed government, which wants to restart the peace process and end 14 years of conflict.
The Afghan army is fighting to regain control of parts of Helmand province in the south.
The UN has raised its threat level for roughly half the country to "high" or "extreme" for the first time since the US invasion in 2001.
And last week, a Pentagon report warned that the security situation in Afghanistan would continue to deteriorate in the face of Taliban resistance.
So, how powerful is the Taliban? And can it be defeated?
Presenter: Dareen Abu Ghaida
Orzala Ashraf Nemat - Governance and civil society specialist at Afghanistan Research and Evaluation Unit.
David Sedney - Senior associate at the Center for Strategic and International Studies.
Habibullah Fawzi - A member of Afghanistan's High Peace Council.
Source: Al Jazeera