WASHINGTON (Reuters) - White House national security adviser Jake Sullivan expressed U.S. concerns over the crisis in the Tigray region in a call with Ethopia’s deputy prime minister, Demeke Mekonnen, the White House said on Thursday. The two “discussed critical steps to address the crisis, including expanded humanitarian access, cessation of hostilities, departure of foreign troops, and independent investigations into atrocities and human rights violations,” in their phone call on Wednesday, the White House said. Ethnic rivalries over land, power and resources have ignited at several flashpoints before national elections scheduled for June in Ethiopia, Africa’s second most populous country. Fighting in the northern Tigray region has killed thousands of people and forced hundreds of thousands from their homes amid shortages of food, water and medicine. Ethiopian Prime Minister Abiy Ahmed has said Eritrea agreed to withdraw troops it had sent into Ethiopian territory along their mutual border. Eritrea has denied its forces joined the conflict. The State Department said on Monday the United States is looking into reports of human rights abuses and atrocities in Tigray. The White House said Sullivan and Mekonnen also discussed the importance of continued regional dialogue to resolve disputes related to the Grand Ethiopia Renaissance Dam, a giant Blue Nile hydroelectric project that has raised concerns in Sudan and Egypt.