Ethiopian soldiers destroyed Unicef's satellite equipment in war-torn Tigray on Monday.
"Members of the Ethiopian National Defense Forces entered our office in Mekele, Tigray, Ethiopia today and dismantled our VSAT equipment," the UN Children's Fund said. "Unicef's priority in Tigray, and across Ethiopia, is to help the most vulnerable children, including the 140,000 children already facing famine-like conditions. We are not, and should never be, a target."
Stephane Dujarric, the spokesman for the UN secretary general, condemned "any and all attacks on humanitarian workers and assets".
Unicef said earlier this month that tens of thousands of malnourished children were at risk of dying in the Tigray region, which has been mired in conflict between federal troops and the regional ruling Tigray People's Liberation Front since November.
Intense fighting has persisted throughout the region, with mounting reports of massacres and widespread sexual violence.
Prime Minister Abiy Ahmed's government announced a unilateral ceasefire on Monday, state media reported, signalling a potential turning point.
Ethiopian authorities have denied the humanitarian situation in the northern region is as dire as aid agencies say, even as the UN report some 350,000 have been pushed to the brink of famine.