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The Pentagon on Monday formally suspended a major military exercise planned for August with South Korea, a much-anticipated move stemming from President Donald Trump's nuclear summit with North Korean leader Kim Jong Un.

Dana White, spokeswoman for the Defense Department, said planning for the summer drills has stopped, but there have been no decisions made on any other military exercises with South Korea. Military exercises with other countries in the Pacific will continue.

Speaking at a news conference last Tuesday after his summit with Kim, Trump abruptly announced that he was suspending military exercises with the South, "unless and until we see the future negotiation is not going along like it should." He added that dumping the drills will save the U.S. "a tremendous amount of money. Plus, I think it's very provocative."

His announcement appeared to catch U.S. defense officials by surprise, and his comments ran counter to long-held American arguments that the exercises are critical for effective operations with allies and are defensive in nature. The Pentagon has for years flatly denied North Korean assertions that the exercises are "provocative."

But as the days went by, the U.S. and Seoul began discussions about temporarily suspending the large Ulchi Freedom Guardian exercises that usually take place in August and possibly other joint drills while nuclear diplomacy with North Korea continues. Seoul's Defense Ministry said Friday that Defense Minister Song Young-moo held "deep" discussions about the drills with U.S. Defense Secretary James Mattis in a telephone conversation Thursday evening.

Trump's decision to suspend the exercises, coupled with the vague joint statement issued after his summit with Kim, have reinforced fears in South Korea that the North is attempting to take advantage of a U.S. president who appears to care less about the traditional alliance than his predecessors.

Last year's Ulchi Freedom Guardian went on for 11 days in August and involved about 17,500 U.S. troops. Also participating were troops from nations that contributed forces during the 1950-53 Korean War, including Australia, Britain, Canada and Colombia.

The other major U.S. exercises with South Korea — Key Resolve and Foal Eagle — took place earlier this spring. They historically include live-fire drills with tanks, aircraft and warships and feature about 10,000 American and 200,000 Korean troops. The drills typically begin in March but were delayed a bit because of the Winter Olympics in South Korea in February.

North Korea has always reacted to the Ulchi exercises with belligerence and often its own demonstrations of military capability.

During last year's Ulchi exercises, North Korea fired a powerful new intermediate-range missile over Japan in what its state media described as a "muscle-flexing" countermeasure to the drills.

Military readiness and lethality have been key priorities for Mattis, so it is still not clear what, if any, smaller exercises may be conducted in the region with South Korea or if more desktop drills may be planned to compensate for the lack of larger, more coordinated events with various ships, aircraft and thousands of troops.

Defense officials are also scrambling to pull together cost estimates for the various exercises with the South to inform Trump's assertion that the suspension will save an enormous amount of money. Mattis's office sent out a request to military commands last Wednesday seeking information on costs, but the Pentagon has yet to provide a public answer.