The Nasa satellite photos have been shared with the BBC as Ethiopian troops and militias, along with soldiers from neighbouring ally Eritrea, appear to be gaining the upper hand against Tigrayan forces.

On Tuesday, Ethiopia said its army had taken control of Shire, one of Tigray's biggest cities, and the towns of Alamata and Korem, which lie to the south of the regional capital, Mekelle.

The UN, African Union and the US, among others, warn that the resurgence of heavy warfare could worsen the already catastrophic situation for civilians.

New data from the Tigray Bureau of Health, shared with the BBC, reveals how the blockade on the region - which has largely halted humanitarian aid as well as other services like electricity and banking - has affected young children.

The figures show that the number of those under the age of five who have died from malnutrition has risen by a staggering 1,533% over the two years from July 2020 - four months before the war broke out.

Dr Kokeb Hagos, who collates the Tigray Health Bureau data, told the BBC that 2,450 children had died in hospitals between July 2021 and July 2022 - a huge underrepresentation, he says, of the true figure as health workers cannot travel around the region because of a shortage of fuel while phone lines and the internet have alsoA recent academic study estimates total civilian deaths in Tigray - caused by the fighting,starvation and lack of health care - stand at between 385,000 and 600,000

Numbers have to be jotted down on pieces of paper and sent by any available transport to the bureau for collation, including the information that 70% of children found to be severely malnourished have not been treated because of a lack of food and medicine.

One of the children known to have died this year is Surafeal Mearig. The BBC first reported on his case in January 2022. At the time he was three months old and weighed just 2.3kg (5lb), 1kg less than he did at birth. His parents had run out of money to buy food after they lost their jobs. Doctors at Mekelle's Ayder Referral Hospital, where he was being treated, told us he died a month later.

Hydroelectric dam bombed

In Nasa's Black Marble images (from November 2020 until August 2022) the trajectory of the conflict can almost be mapped - as they show light levels decreasing in the cities of Shire, Aksum and Mekelle. It is a monthly composite of the light emitted from the respective cities and an indication of their access to electricity.

Ethiopia's federal government controls the national power grid but has been accused of cutting off Tigray, where power was pretty consistent in the region's towns before the war, several sources have told the BBC.

According to an investigation published in September by the UN's International Commission of Human Rights Experts on Ethiopia, the government "suspended electricity, internet and telecommunications, and banking services in Tigray on 4 November 2020" - the day the conflict started.

The images show a sharp fall in light over the cities of Shire and Aksum from November 2020. The lights in the two cities get stronger between March and June 2021 when they are in government hands.

Mekelle remains well-lit until July 2021, just after the city was recaptured by Tigray forces. It had fallen within the first month of the conflict and remained bright during the seven months it was under government control.

"When Tigrayan forces retook control of large parts of Tigray, including Mekelle, in late June 2021, the federal government responded by again shutting down electricity, internet and telecommunications, and banking services for the region," the UN report says.

During the conflict the only major power source for Tigray's seven million people has been the Tekeze Hydroelectric Dam, which was bombed in December 2021.

The images show how the lights dimmed sharply in Mekelle later in December 2021 after the dam was bombed. This affected two of four turbines, according to Canada-based academic Getachew Assefa.

"Engineers are making two turbines active by utilising spare parts from the other two, but the condition is dire. Even the two turbines that are working are generating electricity inefficiently as they have several faults that could have been rectified if spare parts were accessible," the associate professor of sustainable design at Calgary University told the BBC.

Tigray is also home to the 84-turbine Ashegoda windfarm, dubbed Africa's biggest when it opened in 2013 near Mekelle, but it has been out of action during the conflict, says Prof Getachew. been cut.