Ethiopian ethnic separatist rebels have looted warehouses full of US-provided food aid meant for starving people in across the north.
The US Agency for International Development (USAID) said on Tuesday the Tigray People's Liberation Front (TPLF) had raided its warehouses in the Amhara region over the past three weeks.
After regaining control of the Tigray region from the Ethiopian army in July, the TPLF invaded the neighbouring Amhara and Afar regions, displacing hundreds of thousands of residents.
"We do have proof that several of our warehouses have been looted and completely emptied in the areas, particularly in Amhara, where TPLF soldiers have gone into,” USAID Ethiopia director Sean Jones told national broadcaster EBC.
"I do believe that the TPLF has been very opportunistic," he added.
USAID says some 900,000 people in Tigray are already starving, with up to 5 million more in need of aid.
The accusation was in contrast to last week, when the US agency claimed the government was blocking aid to Tigray and warned that its staff would soon run out of food to dole out for the first time in the nine-month civil war.
The US has not remained neutral in the conflict, however, imposing unilateral sanctions on both Ethiopia and neighbouring Eritrea in May.