The US and South Korea have confirmed they will no longer hold two large-scale joint military exercises.
The drills, which have always infuriated North Korea, will be replaced by a smaller-scale joint exercise.
The alliance's defence chiefs said the decision supported "diplomatic efforts to achieve complete denuclearization of the Korean Peninsula".
A smaller series of drills will instead take place, starting on Monday.
North Korea has long regarded the US-South Korean drills as preparation for an invasion.
After US President Donald Trump's historic meeting with North Korea's Kim Jong-un last year, a number of exercises were suspended.
Then on a phone call on Saturday, defence ministers from the US and South Korea agreed to end the Foal Eagle and Key Resolve series of exercises.
South Korea's military said on Sunday the two countries would instead conduct a new, smaller military exercise called Dong Maeng from 4 to 12 March.
"Dong Maeng, which means alliance in English, has been modified from the previously held spring exercises Key Resolve and Foal Eagle and will focus on strategic, operational and tactical aspects of general military operations on the Korean Peninsula," the two militaries said in a joint statement.
The #ROK joint Chiefs of Staff and the ROK-US Combined Forces Command will conduct exercise #DongMaeng March 4-12.— U.S. Forces Korea (@USForcesKorea) March 4, 2019
대한민국, 평택 캠프 험프리즈ㅡ대한민국 합동참모본부와 한미연합사는 “동맹” 연습을 3월 4일부터 12일까지 실시한다.#Training #Readiness #PressRelease@USEmbassySeoul pic.twitter.com/hptYJRNkg4
Critics have said cancelling the drills could undermine US and South Korean military defences against the North, but others say those concerns are unjustified.
Foal Eagle was the largest of the regular joint exercises held by the two militaries. In the past, it has involved as many as 200,000 South Koreans and the roughly 30,000 US personnel based in South Korea.
Key Resolve was a computer-simulated exercise alongside Foal Eagle.
President Trump has previously complained of the cost of such exercises, although he has ruled out withdrawing US troops from the peninsula.
President Trump said he had to "walk" because the North Koreans had demanded the full lifting of economic sanctions before denuclearisation.
But North Korea's foreign minister said Kim Jong-un had asked only for partial sanctions relief in exchange for disabling the main nuclear complex at Yongbyon.