In parts of Ethiopia's Tigray region, people are now forced to eat only green leaves for days. At a health center last week, a mother and her newborn, weighing just 1.7 pounds, died from starvation.

In every district of the more than 20 where one aid group works, residents have starved to death. For months, the United Nations has warned of famine. Now internal documents and witness accounts reveal the first starvation deaths since Ethiopia's government in June imposed what the U.N. calls "a de facto humanitarian aid blockade."

Forced starvation is the latest chapter in a conflict where ethnic Tigrayans have been massacred, gang-raped and expelled. Months after crops were burned and communities were stripped bare, a new cause of death has set in. The U.N. calls it the world’s worst hunger crisis in a decade.

"You are killing people," Hayelom Kebede, the former director of Tigray’s flagship Ayder Referral Hospital, recalled telling Ethiopia's health ministry in a phone call this month. "They said, ‘Yeah, OK, we’ll forward it to the prime minister.’ What can I do? I just cry."

Hayelom shared with The Associated Press (AP) photos of a few of the 50 children receiving "very intensive care" because of malnutrition, some of the first images to emerge from Tigray in months.

In one, a small child stares straight into the camera, a feeding tube in his nose, a protective amulet lying in the pronounced hollow of his throat.

The blockade marks a new phase in the 10-month war between Tigray forces and the Ethiopian government, along with its allies. Now the United States has issued an ultimatum: Take steps to stop the fighting and let aid flow freely, or new sanctions could come within weeks.

The war began as a political dispute between the prime minister, 2019 Nobel Peace Prize winner Abiy Ahmed, and the Tigrayans who had long dominated Ethiopia's repressive national government. In June, the Tigray forces fighters retook the region of 6 million people, and Ethiopia's government declared a cease-fire, citing humanitarian grounds.

Instead, it has sealed off the region tighter than ever. More than 350,000 metric tons of food aid are positioned in Ethiopia, but almost none of it can get into Tigray.

The government is so wary of supplies reaching the Tigray forces that humanitarian workers boarding rare flights to the region have been given an unusual list of items they cannot bring: dental floss, can openers, multivitamins and medications, even personal ones. The list, obtained by the AP, also banned means of documenting the crisis such as hard drives and flash drives.

Tigray has returned to darkness, with no telecommunications, no internet, no banking services and very little aid. Ethiopia's prime minister and other senior officials have denied there is hunger in Tigray. The government blames the Tigray forces and insecurity for troubles with aid delivery and says it has reduced the number of checkpoints that slowed convoys. It also has accused humanitarian groups of supporting the Tigray fighters. The prime minister’s spokesperson, Billene Seyoum, did not say when the government would allow basic services to the region.

The government "has opened access to aid routes by cutting the number of checkpoints from seven to two and creating air bridges for humanitarian flights," she said in a statement. However, medical supplies on the first European Union airbridge flight were removed during government inspection.

In the most extensive account yet of the blockade's toll, a humanitarian worker told the AP that deaths from starvation are reported in "every single" district of the more than 20 in Tigray where one aid group operates. The group had run out of food aid and fuel. The worker, like others, spoke on condition of anonymity for fear of retaliation.

"Currently, there are devastating reports coming from every corner," the aid group wrote to a donor in August, according to documents shared with the AP. In April, the group wrote that 22 people in one subdistrict had starved to death. In August, another staffer visited a community in central Tigray and wrote that some people "are eating only green leaves for days."

One aid worker who recently visited Tigray described the effects of the deprivation: Some toilets in crowded camps for the displaced are overflowing without the cash to pay for their cleaning, leaving thousands of people vulnerable to outbreaks of disease. People who ate three meals a day now eat only one. Camp residents rely on the charity of host communities who often struggle to feed themselves.

"It’s worse than subsistence," the aid worker said. At least 150 people starved to death in August, including in camps for displaced people, the Tigray External Affairs Office has alleged. The International Organization for Migration (IOM), the U.N. agency which supports the camps, said: "We, unfortunately, are not able to speak on this topic."

Food security experts months ago estimated that 400,000 people in Tigray face famine conditions, more than the rest of the world combined. But the blockade means experts cannot collect needed data to make a formal declaration of famine. Such a declaration would be deeply embarrassing for Ethiopia, which in the 1980s seized the world’s attention with famine so severe, also driven by conflict and government neglect, that some 1 million people died. Now malnutrition rates are near 30% for children under 5, the U.N. World Food Programme said Wednesday, and near 80% for pregnant and breastfeeding women.

As the war spreads, so might the hunger. Tigray forces have entered the neighboring regions of Amhara and Afar in recent weeks, and some residents accuse them of carrying out acts of retaliation, including closing off supply routes. The Tigray forces deny it, saying they aim to pressure Ethiopia's government to lift the blockade. There is little help coming.

The U.N. says at least 100 trucks of aid must reach Tigray every day. But as of Sept. 8, less than 500 had arrived since July. No medical supplies or fuel have been delivered to Tigray in more than a month, the U.S. says, blaming "government harassment," not the fighting.

On Tuesday, the U.N. issued the first report of its kind showing the number of days remaining before cash or fuel ran out for critical work like treating Tigray’s most severely malnourished. Often, that number was zero.