Ethiopia has foiled an "Eritrean-sponsored terrorist attack" on the multi-billion dollar Great Ethiopian Renaissance Dam, an official told Anadolu Agency Thursday. Zadig Abrha, a deputy spokesman for the government, told Anadolu Agency 13 assailants belonging to the Benishangul Gumuz People's Liberation Movement were killed Tuesday during the attack. Seven other attackers who crossed over into Sudan were later handed back to Ethiopian authorities by the Sudanese government, Abrha said.Ethiopia accuses Eritrea and Egypt of destabilizing the country. Both deny the accusation. Egypt-Ethiopia relations have been tense after controversy over Ethiopia's dam on the Nile River, dubbed the Grand Ethiopian Renaissance Dam (GERD).The $4.2-billion dam expected to generate up to 6,000 megawatts (MW) of power is currently under construction on Ethiopia's Blue Nile near the Sudanese border. In recent years, Egyptian officials have voiced fear that the dam's construction would serve to diminish Egypt's historical share of Nile waters. Lately, Ethiopia, Egypt and Sudan have signed a deal with two French consultancy firms to study the anticipated impact of a massive hydroelectric dam.