Washington CNN  — 

The US, South Korea and Japan agreed this week to shift a planned flight of at least two nuclear-capable B-52 bombers so they would not fly over the Korean Peninsula, according to two US defense officials.

The decision was made in the wake of North Korea’s objection to US military exercises in the region and a suggestion from Pyongyang that the upcoming summit between Kim Jong Un and President Donald Trump could be at risk.

North Korea threatened to cancel the planned summit between President Donald Trump and Kim Jong Un scheduled for June 12 in Singapore, saying the US should carefully consider the fate of the upcoming meeting, in view of what it calls “provocative military disturbances with South Korea,” North Korea’s state news agency reported early Wednesday local time.

Officials said Friday it was not clear to them whether the decision to shift the route of the aircraft was in response to Kim’s statement but noted the move was part of an effort to try to ease the prospect of North Korea being able to claim the US was engaging in provocative behavior.

The officials insist the bomber missions, which have been going on for several years, are not considered military exercises.

Officially, the Pentagon refused to comment.

“We continue to coordinate with our allies but for operational security reasons we cannot comment on future or ongoing operations. This would also include our decision-making process,” said Pentagon spokesman Lt. Col. Christopher Logan.

But Logan also noted “continuous Bomber Presence missions are part of a routine, forward deployed, deterrence capability supporting regional security and our allies in the Indo-Pacific region.”

Speaking on Friday, the officials said the B-52s which took off from Guam and landed back there, were on a flight that began 24-48 hours earlier. They flew south/southeast of the Korean Peninsula but stayed out of South Korean airspace.

The Wall Street Journal was first to report the altered plans.

On Thursday, the Pentagon told CNN that the decision not to include B-52 bombers in the ongoing Max Thunder military drills “was made long before the DPRK’s remarks on May 16 about diplomatic meetings and summits.”

“The B-52 non-participation is NOT tied to this week’s events or communications. The Republic of Korea and United States will continue to cooperate fully to set the conditions for successful diplomatic efforts while maintaining a foundation of military readiness,” a statement from the Pentagon said.

US bombers have been seen regularly over the Korean Peninsula in recent months amid escalating tensions with Pyongyang – running regular training flights with Japanese and South Korean fighter jets that often provoke the ire of the North Korean regime.