Updated

The Latest on the North Korea crisis (all times local):

4:25 p.m.

The top U.S. military officer says the U.S. will not negotiate away its joint exercises with South Korea as long as the threat of an attack by North Korea exists.

Marine Corps Gen. Joseph Dunford told reporters Thursday that he's advised the U.S. leadership not to dial back on the exercises with South Korea.

Dunford says: "As long as the threat in North Korea exists we need to maintain a high state of readiness to respond to that threat."

North Korea claims the annual drills, scheduled for later this month, are a prelude for an invasion.

Washington and Seoul say the exercises are defensive in nature and crucial to deterring North Korean aggression.