The Taliban were forced from power after a US-led invasion in 2001, but their fighters have become resurgent in recent months.
Taliban operations reached their height with suicide bombings being used as a common method of attack.
More than 50 people died in a suicide bombing near the northern town of Pul-i-Khumri, about 150 km north of the capital Kabul, earlier this week.
Six parliament deputies died in the attack, the deadliest suicide bombing committed during the Taliban-led insurgency.
Exclusive pictures taken by Al Jazeera in the southern province of Helmand within the last few days show that the Taliban remain strong in southern Afghanistan.
Mullah Enqiadi, a Taliban commander in Musa Qala, Helmand, told Al Jazeera's Nazanine Moshiri: "We have achieved more this year compared to last year. We are so strong now, we are able to fight the Americans in Helmand … and on the front-line.
"We are better equipped and our enemies have tried to occupy our territory, but they can't."
Musa Qala was formerly controlled by British troops within Nato's International Security Assistance Force (Isaf).
In October the Isaf contingent made a peace deal with local Afghan tribal leaders but four months later the Taliban took control of the district.