The Democratic People's Republic of Korea on Tuesday cast doubt on a summit with the United States, and suspended talks with the Republic of Korea in response to the two allies' "provocative" military drills, but Washington said it would continue preparing for the historic meeting.

In view of the recently provocative acts such as the Republic of Korea and US joint military drills, the DPRK has no choice but to suspend high-level talks with the ROK planned for Wednesday, the official KCNA said on Wednesday local time.

The state media also said the US should think twice about the fate of the planned DPRK-US summit.

The move appeared to mark a break in months of warming inter-Korean relations and against the momentum that has been building up between Washington and Pyongyang.

Trump has raised high expectations for a successful meeting with Kim, which is scheduled for June 12 in Singapore. He envisioned "a special moment for world peace" and hoped to score one of the biggest diplomatic feats of his presidency.

The KCNA said that the 2018 Max Thunder joint air combat exercise involves over 100 warplanes including B-52 strategic bombers and F-22 Raptor stealth fighters, and is aimed at launching pre-emptive strikes against the DPRK as well as taking control of the airspace.

The exercise is a "blatant challenge to the Panmunjom Declaration and an intentional military provocation" that goes against the trend of warming ties on the Korean Peninsula, the report said.

Shortly after the report, US State Department spokeswoman Heather Nauert said Washington had no information about a threat to cancel the summit.

"We have not heard anything from that government or the government of South Korea to indicate that we would not continue conducting these exercises or that we would not continue planning for our meeting between President Trump and Kim Jong-un next month," she told a briefing.

"We will continue to go ahead and plan the meeting," she said.

The White House said on Tuesday that the US is aware of South Korean media reports about the DPRK's cancellation of planned high-level talks with South Korea.

"The United States will look at what North Korea has said independently, and continue to coordinate closely with our allies," White House spokeswoman Sarah Sanders said in a statement.

US Senator Rand Paul said the DPRK has been long protesting the joint ROK-US military drills.

"I'm hoping it's a temporary setback, and that is their way of protesting against the military exercises," Paul said in a TV interview on Tuesday. "But overall, I'm still optimistic that there will be a meeting and there is a peaceful solution."

Joshua H. Pollack, the editor of The Nonproliferation Review and a senior research associate, said he was not sure if the DPRK's move reflected "irritation with the triumphalist tone from US officials".

"The bottom line, for now: the North Koreans aren't happy with what they're seeing and hearing," he said on Twitter on Tuesday. "There is still a yawning gulf between expectations for diplomacy in Pyongyang and Washington."

Xinhua contributed to this story.