Afghan government forces have pulled out of two districts in the southern province of Helmand.
Provincial Governor Khan Rahimi said the army had "retreated" from two army bases in Musa Qala and one base in Nawzad district, leaving no troops in those districts.
Rahimi added that the soldiers moved to other parts of Helmand.
"Currently for us Sangin, Marjah, Nad Ali, and surrounding areas of Lashkar Gah and Kabul-Herat highway are a priority," military spokesman Mohammad Rasoul Zazai said.
According to a spokesman for NATO's Resolute Support mission in Kabul, U.S. Army Colonel Michael Lawhorn, the Afghan military was making "a tactical decision to reposition forces to fight the Taliban more effectively."
Helmand, a major center of opium production, has been slipping out of government control for months as militants overrun much of the countryside.
Based on reporting by Reuters and AFP