UN chief Antonio Guterres called Friday for the opening of humanitarian corridors to assist civilians caught in fighting in Ethiopia's Tigray region, noting that authorities had so far rejected attempts at mediation. "We are very worried about the situation in Ethiopia," the secretary general told reporters in New York, warning of a "dramatic humanitarian impact" including in neighboring Sudan. "We have been asking for the full respect of international humanitarian law and also for the opening of humanitarian corridors, he said, adding that "until now, there has not been the acceptance by the Ethiopian authorities of any form of external mediation." prh/ec/ft