General David Richards, a British officer who commands 32,000 troops in Afghanistan, said that if life doesn't get better over the winter, 70 per cent of Afghans could get behind the Taliban.
"They will say, 'We do not want the Taliban but then we would rather have that austere and unpleasant life … than another five years of fighting'," he said.
Afghanistan is going through some of the worst violence since the US-led invasion removed the Taliban from power five years ago.
The Taliban has made a comeback in the south and east of the country and is seriously threatening attempts to stabilise the country after almost three decades of war.
Richards will command Nato's forces in Afghanistan, including 12,000 US troops, until February, when US General Dan K McNeil will take over.
The British general said he would like to have about 2,500 additional troops to form a reserve battalion to help speed up reconstruction and development efforts.
The south of the country, where Nato troops have fought their most intense battles this year, has been "broadly stabilised", Richards told Associated Press.
Meanwhile, authorities in the north of the country have identified up to six people they want to question about the killing of two German journalists shot dead while camping, a senior official said on Sunday.
The Germans, a woman and a man who had worked for Deutsche Welle radio, were killed in the early hours of Saturday when assailants attacked them in their tent in Baghlan province, about 120km north of Kabul.
"We have identified from four to six people in the area where the attack took place," Sayed Ikram Mahsomi, the governor of Baghlan, said. "We are going to make arrests as soon as we get more information".
British soldiers are bearing the
brunt of the Taliban resurgence
Mahsomi said that the Germans had not been robbed and called the attackers "government opponents". "They just wanted to kill them to disrupt security," he said.
The German radio station identified the victims as freelance journalists Christian Struwe and Karen Fischer.
Qari Mohammad Yousuf, a Taliban spokesman, said they did not carry out the killings.