"We took the step to suspend several of the largest military exercises as a good faith measure," Defense Secretary Jim Mattis told reporters. "We have no plans to suspend any more."

Mattis, however, did not give any indication that exercises with allied forces in the region -- which have angered Pyongyang in the past -- would resume any time soon.

"We are going to see how the negotiations go, and then we will calculate the future, how we go forward," Mattis said.

In June, after Trump met with Kim in Singapore, the United States said it would suspend "select" exercises with South Korea, including the large-scale Ulchi Freedom Guardian exercises slated for August, making good on a Trump summit pledge.

Some 17,500 US military personnel were due to take part in the Freedom Guardian drills.

In June, Trump raised eyebrows by describing the exercises as "war games" and as "provocative" -- a term used by the North.

Mattis demurred when asked if a resumption of exercises could now be considered provocative.

"Even answering a question in that manner could influence the negotiations. Let's let the negotiations, let the diplomats go forward. We all know the gravity of the issues we are dealing with," he said.

US and South Korean forces have been training together for years, and routinely rehearse everything from beach landings to an invasion from the North, or even "decapitation" strikes targeting the North Korean regime.