UNITED NATIONS: The United Nations humanitarian aid chief Stephen O'Brien voiced serious concern on Thursday that authorities in Luhansk in eastern Ukraine are demanding that all UN agencies immediately vacate the city.

"I am alarmed by news that the de facto authorities in eastern Ukraine have ordered UN agencies in Luhansk to end operations and to leave the area by tomorrow, 25 September," O'Brien said in a statement. Eastern Ukraine is controlled by pro-Russian separatists who reject the Kiev government.

"I am also extremely concerned by the situation regarding accreditation and registration of international NGOs (non-governmental organizations) in Donetsk," he added. "A decision by the de facto authorities in Donetsk on the UN's future operations remains on hold, and all UN agency operations have been suspended."