North Korea ? North Korea said today it must bolster its nuclear capability to cope with “hostile” U.S. policy amid high tension over the deadly sinking of a South Korean warship blamed on Pyongyang.

An international investigation concluded last month that North Korea torpedoed the warship Cheonan near the tense Korean sea border. North Korea flatly denies the allegation and has warned any punishment would trigger war.

The statement from the North’s Foreign Ministry, carried by the official Korean Central News Agency, didn’t elaborate how North Korea would strengthen its nuclear capability.

North Korea cites the threat of a nuclear attack from the U.S. as a main reason behind its drive to build atomic weapons.