Hamidullah says he is a member of the Taliban fighting against Operation Moshtarak - a joint Afghan-Nato offensive centred around Marjah, in Afghanistan's southern Helmand province.
He told Al Jazeera that the foreign troops' offensive is not succeeding, as they often kill civilians instead of Taliban fighters.
As a result, he says the Afghan people now support the Taliban more than before.
His statements come after a Nato air strike on what was assumed to be a bus carrying Taliban fighters on Sunday, killed 33 Afghan civilians.
Al Jazeera spoke to Hamidullah in an exclusive interview in Lashkar Gar, Helmand's capital city.
Source: Al Jazeera