US Secretary of State Mike Pompeo on Wednesday downplayed North Korea's latest missile launches, saying they won't alter the prospects for negotiations on Pyongyang's nuclear weapons.

One day after North Korea called a new round of short-range missiles a "warning" against joint US-South Korea military exercises, Pompeo told reporters that it didn't impact Washington's approach to the region.

The latest launches were the fourth pair of projectiles fired in less than two weeks by the North. They came after the South Korean and US militaries began mainly computer-simulated joint exercises on Monday to test Seoul's ability to take operational control in wartime.

Asked if the missile launches dampened  the environment for negotiations on denuclearization, Pompeo replied "No." "President Trump's administration strategy with respect to North Korea hasn't changed," he said.

"Our effort is to achieve the full, final denuclearization of North Korea. We are hopeful that in the coming weeks we will get back to negotiating table to achieve that."

Pompeo noted that the recent launches by North Korea did not involve the medium and long-range ballistic missiles that had raised alarms in 2017 and 2018, and that Pyongyang has stopped testing nuclear weapons since September 2017.

"Those are both good things," he said.

"Now the task is for us to deliver on want the two leaders agreed to back in June of last year in Singapore," he said, referring to meetings between President Donald Trump and North Korean leader Kim Jong Un, when the North made a vague pledge on denuclearization.

"We are fully focused on that and we are planning for negotiations in a couple of weeks and we anticipate the two teams getting back together." During an impromptu June meeting in the Demilitarized Zone that divides the peninsula the two leaders had agreed to resume talks, but working-level dialogue has yet to begin.

Analysts say the military maneuvers on both sides could see discussions pushed back until the autumn, and Pyongyang signalled Tuesday that it was in no mood to talk.

It called the drills a "flagrant violation" of the diplomatic process between Pyongyang, Washington and Seoul.