The U.S. ambassador to the United Nations, Nikki Haley, warned North Korea on Tuesday against staging another missile test and said Washington would not take any talks between North and South Korea seriously if they did not do something to get Pyongyang to give up its nuclear weapons.

Haley told reporters the United States was hearing reports that North Korea might be preparing to fire another missile.

"I hope that doesn't happen. But if it does, we must bring even tougher measures to bear against the North Korean regime," Haley said.