United Nations Secretary-General Antonio Guterres said on Thursday that he was gravely concerned by the rapidly deteriorating situation in northern Ethiopia, a day after the federal government and the TPLF accused each other of launching offensives, in what appears to be a return to full-scale conflict. The Secretary-General called on all parties to exercise maximum restraint, immediately de-escalate tensions, protect civilians, ensure safe and unhindered access for humanitarian partners to reach those in need, and avoid actions that could lead to a broader and more devastating conflict. Ethiopian Airlines said that flights to Mekelle and the cities of Shire and…