Bad news for North Korea: The United States and the United Nations are both looking to take action against the Stalinist country over the deadly sinking of a South Korean warship in March. The U.S. announced that it will begin conducting joint naval exercises with South Korea, with President Obama pledging to “insure readiness and deter aggression.” The exercises would help South Korea improve its ability to detect enemy submarines and stop banned shipments of nuclear materials. “The Republic of Korea can continue to count on the full support of the United States,” Secretary of State Hillary Clinton said from Beijing. “Our support for South Korea’s defense is unequivocal.” Meanwhile, U.N. Secretary-General Ban Ki-moon announced that action would be taken over the incident, though no specifics were given. Earlier Monday, South Korea announced that it was halting trade with its northern neighbor, which could cripple the impoverished nation.