The murder of 11 Chinese construction workers and the killing of five Medecins sans Frontieres employees have stunned Afghanistan's aid community.
Aid workers once felt safe in Afghanistan but are now uneasy
"We are deeply shocked and appalled by both these incidents," said Barbara Stapleton of the Agency Coordinating Body for Afghan Relief.
"The Chinese incident highlights the government's failure to protect people or to expand its authority," she said.
"The international community hasn't taken adequate measures to support it."
According to Nick Downie of the Afghanistan NGO Security Office, "people cannot believe what has happened. What's clear is that some actors can carry out murder with impunity on the softest targets".
The disbelief is all the greater given that Thursday's killings - of workers for a Chinese company rebuilding a road - and those of the medical aid workers happened in northern Afghanistan, previously considered much safer than the south and east, where an insurgency blamed on Taleban and al-Qaeda guerrillas is growing.
The most immediate effect has been a stunned withdrawal of NGO activity.
For Dr Maya Volles of the German NGO, Malteser, which builds schools and runs clinics and a hospital, the reaction is one of "deep, deep shock", and it is an especially personal one.
Until last week, she was based in Badghis province, where the MSF workers were killed.
They were her close friends and colleagues.
"There had never been any problems on that road," she told the BBC from the main western city of Herat.
All NGOs and all expatriate workers have now left Badghis, most of them at the weekend, when an Italian NGO compound was attacked with grenades in the provincial capital.
"We've closed all 14 health centres and withdrawn for a minimum of four weeks," she said. "It's very bad news, but it's too dangerous now."
Another NGO worker in Herat, who did not want to be named, affirmed that "there's none of us left in Badghis except the people guarding our compounds".
Five MSF staff were killed in Afghanistan by Taleban militants
"We're concentrating on our projects in the city, but the greatest need is in the countryside."
Even the agencies not working near Badghis or Kunduz - scene of the Chinese deaths - are reviewing their situation.
"We are constantly monitoring and re-evaluating operations," said Paul O'Brien of Care International, which works mainly in eastern Afghanistan.
"This is the largest loss of life of civilian expatriates in recent memory, and our staff are increasingly at risk."
Aid agencies cannot plan ahead.
Dr Volles says they have written to the governor of Badghis, demanding that a programme to disarm militias be stepped up, but they need time to consider what will come next.
Would NGOs have to adopt armed guards, as some have in Chechnya and Somalia?
"The NGO community is pretty strongly against that," says the unnamed source in Herat.
Barbara Stapleton agrees - it is against their philosophy, she says.
But Paul O'Brien is blunt. "If current security trends continue, it will be all but impossible to continue the reconstruction of Afghanistan," he says.
Nick Downie echoes this view. "They'll move away from regions where they don't feel safe," he warns.
Where, then, would they remain?
"There's no sanctuary," he admitted. "They felt safe, and now they're in fear."