Trump campaign manager Kellyanne Conway, pressed repeatedly on Trump's plan, said only, "He wouldn't do what's being done now."

"He's not going to reveal all of his plans, and he's made that very clear. And maybe someone can ask him in a debate," Conway told CBS "This Morning." ''But the fact is that this entire world would be put on notice that there's a strong leader in the White House."

Democrat Hillary Clinton said North Korea's determination to develop a "deliverable nuclear weapon" represents "a direct threat to the United States."

The former secretary of state, in a statement, called for new sanctions in addition to those endorsed by the Obama administration and adopted earlier in the year with the United Nations.