The European Union on Monday imposed sanctions on Eritrea over human rights violations and blacklisted the country's National Security Office, which is tasked with intelligence gathering, arrests and interrogations.
At the beginning of March, the United Nations said Eritrean troops were operating throughout Ethiopia's northern Tigray region and reports suggested they were responsible for atrocities.
Tigray has been gripped by conflict since November last year when Ethiopia's federal forces moved in and toppled the region's then ruling party, the Tigray People's Liberation Front (TPLF).
In a statement, Eritrea rejected the accusations, saying they were trumped up and the sanctions had no legal basis.