Safety fears following the kidnapping of a leading US worker have forced a number of major aid groups to suspend projects in Chechnya.
The United Nations and Medecins Sans Frontieres (MSF) announced they were suspending operations after gunmen seized the head of MSF's North Caucasus mission, Mr Kenny Gluck, on Tuesday.
Hundreds of thousands of displaced Chechens are now facing into the freezing winter without adequate shelter, food and medical care, MSF said.
A planned World Food Programme shipment to about 90,000 Chechens has also been halted by the UN.
MSF said it was looking at the situation but had taken the precaution of halting its work for now.
Moscow's second onslaught in six years against Chechen separatists began in late 1999 and has displaced some 300,000 Chechens and flooded Ingushetia with about 150,000 refugees.
International aid agencies supply them with food, medicines, blankets and plastic sheeting for shelter, but with no end in sight to the conflict and winter gripping the region, charities say Chechens need all the help they can get.
Mr Gluck was seized when gunmen opened fire on a column of vehicles on Tuesday in Starye Atagi, about 12 miles south of the regional capital Grozny. It is the scene of the bloodiest chapter in the history of aid work in Chechnya.
In 1996 masked gunmen murdered six foreign workers, including five women, in an International Committee of the Red Cross (ICRC) hospital in the town, bursting in at night and shooting them in their beds. The ICRC has refused to base international workers in the region since.
Reuters