Ethiopian authorities have detained more than 70 drivers working with the United Nations, an internal U.N. email seen by Reuters on Wednesday said, amid reports of widespread arrests of ethnic Tigrayans.

The ethnicity of the drivers was not clear. On Tuesday, a U.N. spokesperson said that at least 16 U.N. staff and dependents had been detained in the Ethiopian capital Addis Ababa. The detained drivers were in addition to those detained staff, the email said.

Ethiopian government spokesperson Legesse Tulu and foreign affairs ministry spokesperson Dina Mufti did not immediately respond to a request for comment on the detention of the drivers. A spokeswoman for the U.N. contingent in Ethiopia told Reuters it would email a response shortly.

On Tuesday, when asked about the arrest of U.N. contractors such as drivers, a U.N spokesman in New York said it was investigating.

The head of the state-appointed Ethiopian Human Rights Commission said on Tuesday they had received hundreds of reports of Tigrayans being arrested in the capital.

Police have denied making ethnically motivated arrests, saying they are only targeting supporters of the rebellious Tigrayan forces fighting the central government.

War broke out last year between the federal government and the Tigray People’s Liberation Front (TPLF), who used to dominate the ruling coalition in the country.