NEW YORK, June 15 (Reuters) - Eritrean troops in Ethiopia"s Tigray region are expected to "definitely leave soon," Ethiopia"s U.N. envoy said after a top U.N. official told the Security Council on Tuesday that Eritrea"s soldiers were using starvation as a weapon of war. Outgoing U.N. aid chief Mark Lowcock told the 15-member council in a private briefing that "no one should be surprised to see a rerun" of a devastating 1984 famine if violence in Tigray does not stop and Eritrean troops do not withdraw. "Rape is being used systematically to terrorize and brutalize women and girls. Eritrean soldiers are using starvation as a weapon of war. Displaced people are being rounded up, beaten and threatened," Lowcock told the council, according to diplomats who attended the meeting. Eritrea"s U.N. mission in New York did not immediately respond to a request for comment on Lowcock"s allegation. Eritrea said in April that it had agreed to start withdrawing its troops from Tigray. read more In April, Eritrea"s U.N. ambassador, Sophia Tesfamariam, rejected allegations of sexual violence and starvation by Eritrean troops as false and "outrageous." Ethiopia"s U.N. ambassador, Taye Atske Selassie Amde, who took part in the council discussion, said the Eritrean withdrawal "is a matter of sorting out some technical and procedural issues." "Our expectation is that they will definitely leave soon," he told reporters after the council briefing. Lowcock briefed the Security Council just days after an analysis by U.N. agencies and aid groups found that more than 350,000 people in Tigray are suffering famine conditions - the worst catastrophic food crisis in a decade. read more Ethiopia"s government has disputed the analysis. Amde also said Ethiopia"s government had granted unfettered aid access to Tigray and was grateful for international humanitarian help. The informal council meeting on Tuesday, requested by Ireland, was its sixth private discussion of the crisis since fighting broke out in November between Ethiopia"s federal government troops and Tigray"s former ruling party. Eritrean troops entered the conflict to support the Ethiopian government. "All evidence now points towards an unfolding humanitarian catastrophe," Ireland"s U.N. ambassador, Geraldine Byrne Nason, said in a statement. "People in Tigray are starving and we cannot delay ... we have to ensure that no more lives are lost." Amde said the situation in Tigray did not warrant the Security Council"s attention. Western council members have been pitted against Russia and China, which diplomats say also question whether the body, charged with maintaining international peace and security, should be involved in the crisis in Tigray. The violence in Tigray has killed thousands of civilians and forced more than 2 million from their homes in the mountainous region. In April, the Security Council issued a statement of concern about the humanitarian situation. "It is not drought or locusts causing this hunger, but the decisions of those in power. That means those in power can also end the suffering," British U.N. Ambassador Barbara Woodward told reporters after Tuesday"s briefing. Reporting by Michelle Nichols Editing by Chris Reese