WASHINGTON, Dec 3 (Reuters) - The United States has sanctions authorities at its disposal to use against those perpetuating the conflict in Ethiopia, which is increasing ethnic tensions and risks implosion of the country itself, U.S. Secretary of State Antony Blinken said on Friday. "We"ve used some of them already against Eritrea, which has been, unfortunately a very negative actor in this drama. Those tools remain at our disposal for others," Blinken said at the Reuters Next conference of the conflict in Africa"s second largest nation.