The North conducted two previous rounds of similar short-range launches and other military exercises this month after leader Kim Jong Un entered the new year vowing to bolster his nuclear deterrent in face of "gangster-like'' U.S. sanctions and pressure.

South Korean military officials didn't immediately say what the weapons were, how many were launched or how far they flew.

John Bolton: "The firing of these missiles don't violate the pledge that Kim Jong Un made to the president about intercontinental-range ballistic missiles,"

U.S. President Donald Trump said on Thursday he would leave sanctions in place on North Korea as he and South Korean President Moon Jae-in discussed ways to get U.S.-North Korea nuclear talks back on track after a failed summit in Hanoi.

The North Korean action came a week after its vice foreign minister threatened to pull out of nuclear negotiations with the United States

North Korea's vice foreign minister said the country has "no intention to yield to the U.S. demands (at the Hanoi summit) in any form, nor are we willing to engage in negotiations of this kind."

North Korea said it's ceasing nuclear weapons testing because it has achieved its goal of taking its place among the world's nuclear-armed states, and now wants to focus on improving its economy.

"None of this plays in China," says Ian Bremmer. "They can’t stand this stuff, and Canada’s small."

North Korea hit one of its own cities when a missile test last spring went awry, researchers say.

Donald Trump said Sunday that Secretary of State Rex Tillerson was "wasting his time" trying to negotiate with North Korea.