NEW : North Korea says sanctions over the years only caused it to bolster its nuclear deterrent . China , North Korea 's key ally , could have used its veto power to block the sanctions . The U.N. Security Council voted unanimously to approve new measures . Comment: North Korea responds with a fresh statement of angry threats .
NEW : North Korea says sanctions over the years only caused it to bolster its nuclear deterrent . The U.N. Security Council voted unanimously to approve new measures . Comment: North Korea responds with a fresh statement of angry threats .