North Korea warns of nuclear tests

Korea, Republic Of - North Korean leader Kim Jong Un has warned of impending tests of a nuclear warhead explosion and ballistic missiles capable of carrying atomic warheads, state media reported Tuesday, in an escalation of threats against Seoul and Washington.

The warning came as North Korea said it had made a breakthrough in its pursuit of a long-range missile capable of striking the U.S. mainland. South Korea says the North has yet to develop a functioning inter-continental ballistic missile.

Kim issued the order for the tests "in a short time," according to the Korean Central News Agency. The KCNA report did not say if Kim gave specific dates for the tests.

It is not clear if the tests would happen soon, given that any tests would likely invite harsher international sanctions after the country was hit by the toughest UN Security Council sanctions in two decades in early March for a nuclear test and long-range rocket launch conducted earlier this year.