The attack reportedly took place in a site hosting internally displaced people in the town of Dedebit in Tigray region.
Earlier last week another air strike hit the Mai Aini refugee camp, also in Tigray, resulting in the death of three Eritrean refugees, including two children.
"The United Nations and its humanitarian partners are working with authorities to urgently mobilize emergency assistance in the area, despite continuing challenges due to severe shortages of fuel, cash and supplies across Tigray," said the Spokesman for the UN Chief in a statement on Monday.
Guterres expressed his deepest condolences to the victims and their families.
The Secretary-General reiterated his call for an immediate cessation of hostilities, including air strikes, and for all parties to adhere to their obligations under international humanitarian law to facilitate humanitarian access and to ensure the protection of civilians, including humanitarian actors, premises and sites.