Upcoming military exercises with South Korea have been “suspended indefinitely,” a U.S. official said Thursday.

A formal guidance from the Pentagon for the suspension of planned joint exercises in August will be issued shortly, according to several reports.

The announcement comes two days after President Trump’s stunning promise to stop the “expensive, provocative” missions following his historic summit in Singapore with North Korean leader Kim Jong Un.

Trump’s decision, seen by many as a major concession to Kim, caught South Korean officials and other allies off guard.

The Singapore sitdown with Kim yielded a joint statement with vague promises to work toward a denuclearized Korean Peninsula. Critics have cautioned that North Korea has reneged on similar pledges to disarm in the past.

RELATED: US-South Korea joint military drills

10 PHOTOS US-South Korea joint military drills See Gallery US-South Korea joint military drills South Korean amphibious assault vehicles throw smoke bombs as they make it to the shore during Foal Eagle, March 30, 2015. US Marines and South Korean soldiers await further orders inside their armored vehicle, during a joint combat training exercise. US Marines also train in South Korean vehicles. Here, US Marines run out from a South Korean LVT-7 during a joint landing exercise for Foal Eagle, in Pohang, South Korea, March 31, 2014. US Marines move out with their South Korean counterparts. US and South Korean Marines aim their rifles near their amphibious assault vehicles during Foal Eagle. US Marines from 3rd Marine Expeditionary force deployed from Okinawa, Japan, train with South Korean soldiers in Pohang, South Korea. South Korean and U.S. Marines take part in a winter military drill in Pyeongchang, South Korea, December 19, 2017. REUTERS/Kim Hong-Ji A U.S. Navy crew member works on a U.S. F18 fighter jet on the deck of U.S. aircraft carrier USS Carl Vinson during an annual joint military exercise called "Foal Eagle" between South Korea and U.S., in the Sea of Japan, South Korea, March 14, 2017. REUTERS/Kim Hong-Ji Originally based on the M1 Abrams, the South Korean K1 tank is manufactured by Hyundai Rotem. The South Korean K1 tanks have a range of 310 miles and has a top speed of 40 mph. Air assets, such as the US Navy's F/A-18 Super Hornet, have also been utilized amid the drills. Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Trump’s top diplomat insisted on Wednesday that the President hadn’t backed down from his firm line on North Korea’s nukes.

U.S. Secretary of State Mike Pompeo, meeting in Seoul with top South Korean and Japanese diplomats, noted that "there's a lot of work left to do."

Military officials from the two Koreas, still technically at war since the 1950s, met on Thursday to discuss restoring cross-border communications and reducing tensions.

It wasn’t immediately clear if North Korean officials brought up the military drills with during the talks at Panmunjom.

The annual drills between Washington and Seoul have long been a major source of contention between the Koreas.

Kim’s regime sees them as invasion rehearsals.

Choi Hyunsoo, spokeswoman of South Korea’s Defense Ministry, said Thursday that officials in Seoul and Washington “were closely coordinating and holding discussions” on the exercises.

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