WASHINGTON (Reuters) - United Nations Secretary-General Antonio Guterres on Monday sounded the alarm over Russia raising the alert level for its nuclear forces, describing it a 'bone-chilling development' and added that the prospect of nuclear conflict was back within realm of possibility.

       In remarks at the U.N., Guterres also said the U.N. was going to allocate a further $40 million from its Central Emergency Response fund to ramp up humanitarian assistance for Ukraine.

       (Reporting by Humeyra Pamuk and Chris Gallagher)