Most of the detentions were made in the Ethiopian capital Addis Ababa as well as in Gondar, Bahir Dar and other locations were of Tigrayan origin.
Authorities in Ethiopia have detained at least 1,000 people, most of them of Tigrayan origin, under a state of emergency the government declared earlier this month.
The arrests occurred in Ethiopia's capital, Addis Ababa, the northern cities of Gondar and Bahir Dar, and other places, said Liz Throssell, a spokesperson for the Office of the UN High Commissioner for Human Rights, on Tuesday.
She told reporters that Ethiopian authorities have often detained people on suspicion of “being affiliated to or supporting the Tigray People's Liberation Front."
“The state of emergency in force in Ethiopia risks compounding an already very serious human rights and humanitarian situation in the country,” Throssell said, referring to the November 2 government decree.
“Its provisions are extremely broad, with vague prohibitions going as far as encompassing 'indirect moral' support for what the government has labeled ‘terrorist groups.’”
Ten local UN staff members and some 34 drivers working under UN contracts remain in custody in Ethiopia, Throssell said.
She expressed concerns about detention conditions, including in overcrowded police stations, and said detainees are entitled to know any charges against them and have a right to fair trial.
Ethiopia’s war has killed thousands of people and created one of the world’s worst crises.
Hundreds of thousands face famine conditions in the Tigray region under what the United Nations has called a “de facto humanitarian blockade.”
Months of political tensions in northern Ethiopia between Prime Minister Abiy Ahmed’s government and the Tigray leaders who once dominated Ethiopia’s government exploded into a war in November 2020.
Following some of the fiercest fighting of the conflict, Ethiopian soldiers fled the Tigray capital, Mekele, in June.
Tigray forces launched a recent offensive and are approaching the capital Addis Ababa to press Abiy to step aside and lift a deadly months-long blockade which has cut off food, medicine and other aid from the region of around 6 million people.