The United States aid agency USAID has announced it is halting food aid to all of Ethiopia, a month after pausing aid to the war-torn Tigray region, citing illicit diversions.

The agency on Thursday cited “a widespread and coordinated campaign” to divert aid from those in need as the reason for the suspension in Ethiopia, which has grappled with rampant hunger amid civil war and drought.

“We made the difficult but necessary decision that we cannot move forward with distribution of food assistance until reforms are in place,” said a statement by a spokesperson for the US government’s main international aid agency.

“Our intention is to immediately resume food assistance once we are confident in the integrity of delivery systems to get assistance to its intended recipients,” the statement added.

The statement did not say who was behind the diversions, but in a separate statement released hours late by the US Embassy in Ethiopia, both governments said they were conducting “investigations so that the perpetrators of such diversions are held to account.”

“The two governments commit to collaborate toward an efficient aid distribution system in Ethiopia, which would safeguard assistance from diversion,” it said.

The pause comes after USAID and the World Food Programme froze food aid to the Tigray region in northern Ethiopia, where war between regional forces and Ethiopia’s government broke out in November 2020. The two sides agreed to a truce in November last year. The agencies cited the diversion of aid shipments to local markets as the reason for the suspension.

On Thursday, The Washington Post newspaper cited a report by the Humanitarian Resilience Development Donor Group, which it described as an organization of donors briefed by USAID, that identified “a coordinated and criminal scheme” to divert the aid.

The report said the “scheme appears to be orchestrated by federal and regional Government of Ethiopia (GoE) entities, with military units across the country benefitting from humanitarian assistance” and that “significant diversions” had been documented in seven of Ethiopia’s nine regions, according to the Post.

On Thursday, top US diplomat Antony Blinken met with his Ethiopian counterpart, Foreign Minister Demeke Mekonnen, during a trip to Riyadh, Saudi Arabia.

State Department spokesman Matthew Miller said Blinken “welcomed the Ethiopian government’s commitment to work together to conduct a full investigation into the diversion of US food assistance and to hold accountable those found responsible”.

According to the World Food Programme, more than 20 million people across Ethiopia are in need of food assistance. In fiscal year 2022, USAID distributed $1.5bn to the country, most of it in food aid.