The murders, carried out while the victims slept in their beds, are the worst ever violation of the frequently abused neutrality under which Red Cross staff have staked their lives to help victims of countless wars.
They sent a wave of shock and revulsion around aid agencies, deepening their alarm over the growing evidence that their rights are being treated with contempt in conflict zones, and that their workers - often young western professionals - are increasingly at risk.
"There is a dramatic trend in which there is no respect for the Red Cross or other agencies," said Thierry Meyrat, head of delegation for the International Committee of the Red Cross (ICRC) in Moscow. They were being compelled to adopt a more military style, increasing the risk of being made a target.
Other international agencies were also discussing plans to withdraw from the Caucasian republic, at least until the killers were found. Their crime had the hallmarks of a carefully planned operation; the assassins had used guns equipped with silencers.
It happened at around 4am yesterday, when masked men broke into a hospital, a clearly marked Red Cross centre, at the entrance to the small Chechen town of Novye Atagi, 11 miles south-west of Grozny.
They broke down bedroom doors, and shot their victims in bed. The hospital employs 15 expatriates, and 180 locals. None of the latter was hurt, although a foreign worker was injured.
The murdered aid workers were a Dutch architect and nurses from New Zealand, Canada, Spain and Norway. They had been working at the hospital since September, when it was set up, using funds from the Norwegian Red Cross, specially to care for victims of Chechnya's 21-month war.
Although the motive remains uncertain, aid sources were sure it was political. They pointed out that the assassinations looked suspiciously like a calculated attempt to disrupt the republic's elections on 27 January.
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