GENEVA (AFP) - The UN on Friday (Sept 10) condemned the Taliban's increasingly violent response to peaceful protests, including using live rounds that killed several people, and warned that nearly all Afghan households weren't getting enough to eat.

"We call on the Taliban to immediately cease the use of force towards, and the arbitrary detention of, those exercising their right to peaceful assembly and the journalists covering the protests," said Ms Ravina Shamdasani, spokesman for the United Nations human rights office.

Her office said armed fighters had been using live ammunition and whips to disperse crowds, killing at least four people since mid-August.

The Islamist hardliners who swept into power on Aug 15 have pledged a more moderate brand of rule than in their notoriously oppressive 1996-2001 reign.

But they have shown clear signs that they will not tolerate opposition.

Earlier this week, armed Taliban militants dispersed hundreds of protesters in cities across Afghanistan, including in Herat, where two people were shot dead.

Ms Shamdasani said the rights office had also received credible reports that a man and a boy were shot dead as Taliban gunmen sought to disperse crowds during national flag-raising ceremonies held last month.

"Firearms must never be used except in response to an imminent threat of death or serious injury," she said.

On Wednesday, at least five journalists were arrested and two severely beaten for several hours.

"One journalist was reported to have been told, as he was being kicked in the head, that you are lucky you have not been beheaded," she said.

"(There is) lots of intimidation of journalists who are trying to simply do their job," she said.

The Taliban moved to snuff out any further civil unrest late on Wednesday, saying protests would need prior authorisation from the justice ministry.

The following day, it ordered telecommunications companies to block Internet on mobile phone service in some areas of Kabul, Ms Shamdasani said.

Meanwhile the World Food Programme warned that a massive 93 per cent of households in the conflict-racked country were not consuming a sufficient amount of food.

"Three in four families are already reducing portion sizes or borrowing food," according to random phone surveys carried out from Aug 21 to Sept 5 in all of the country's 34 provinces, said WFP deputy regional director for Asia-Pacific Anthea Webb.

"Parents are skipping meals entirely to allow children to eat," she said.

"The proportion of households resorting to extreme coping strategies has doubled - a clear sign that many families are teetering on the edge of absolute destitution," she warned.

The UN is seeking to raise some US$600 million (S$805 million) from donors for Afghanistan at a Geneva conference that starts next Monday.