A government official says seven people have been killed in an explosion in northwestern Ethiopia. Tigray State Vice President Abadi Zemo says a bomb attached to a bus exploded in Humera, about 600 kilometers northwest of the Ethiopian capital, Addis Ababa. Humera is in Tigray State and borders Sudan. Zemo says the Eritrean government is behind the blast. He says: "There is no doubt" of the government's involvement.