The UN refugee agency has blasted Russia-backed rebels in eastern Ukraine for shutting the door on international aid.

More than 8,000 people have been killed by fighting between separatist rebels and Ukrainian government troops. With the Ukrainian government shutting down all public services in the rebel-held areas, aid from international organizations has been crucial for survival there.

The UNHCR said in a statement Friday that rebel leaders in Luhansk announced a decision on Wednesday to expel its staff along with other international agencies. The UNHCR deplored the decision saying that it "comes at a critical time as harsher winter weather is about to hit the region."

The rebels have long been suspicious of foreign aid agencies with some senior separatist leaders openly calling them spies.