The UN humanitarian aid chief has expressed concern after UN agencies were ordered out of rebel-held parts of Luhansk region in eastern Ukraine, the media reported on Friday.
Stephen O'Brien said the agencies had been told to leave by Friday, and several international NGOs by Saturday, BBC reported.
He also said that all UN agency operations had been suspended in the rebel-held parts of Donetsk.
O'Brien urged the separatists in "both Luhansk and Donetsk to ensure the immediate resumption of UN and international NGO activities".
He warned that restrictions on humanitarian shipments had prevented delivery of some 16,000 tonnes of vital supplies.
"Hospitals cannot perform surgery because they lack anaesthesia. Some 150,000 people are not receiving monthly food distributions," the chief said.
On Thursday, the Luhansk rebels refused to register 10 out of 11 foreign NGOs because of "violations".
They accused one of the banned NGOs - Doctors Without Borders - of "illegally storing psychotropic medication". The NGO denied the charge.
Pro-Russian rebels seized parts of the Luhansk and Donetsk regions last year.
Almost 8,000 people have been killed since fighting erupted in eastern Ukraine in April 2014, a month after Russia annexed the southern Crimea peninsula.
