Oil Minister Masoud Mirkazemi said "Afghanistan's private sector buys all its needed products from Iran," the oil ministry news service Shana reported.

"Oil products were already transited to Afghanistan and we hope from now on this country makes all its (fuel) purchases from Iran as there has been an agreement with Afghan officials," Mirkazemi said.

About one-third of Afghanistan's fuel needs, imported from Russia, Turkmenistan and Iraq, transit through Iran.

The transport of the fuel has become a sensitive issue as the Islamic republic has prevented the passage of trucks carrying the supplies to Afghanistan.

Tehran has hinted to Kabul that it suspected the transited fuel would supply US and other foreign troops fighting the insurgency in Afghanistan.