The South Korean military on Wednesday said the joint drills with the US have been cut short at Washington’s request as Donald Trump tries to restore his ties with North Korean dictator Kim Jong Un.

The Ulchi Freedom Shield exercise, which began on Monday, would end on 21 August, almost a week earlier than scheduled, announced South Korea’s joint chief of staff.

Seoul said both nations have agreed to downsize some joint field training exercises “at the request of the US”.

South Korean defence minister, Ahn Gyu Back, said the allies have cancelled the second phase of the drills, which was focused on counterattack operations after an initial defensive phase.

A Pentagon official said the defence department had substantially reduced ​the exercise ⁠and associated live-training events, with some cancelled or switched ‌to simulations. “The changes would preserve essential readiness and training aims, with no degradation to US training objectives,” the official added.

Experts worry that the revised end could potentially harm the defence pact between the two long-term defence allies as president Trump extends his outreach to mend ties with North Korea.

Mr Trump on Sunday issued sudden instructions to his defence secretary, Pete Hegseth, to reduce the exercises based on his “very good relationship” with the North Korean leader. He claimed the days-long annual drill sent a “totally inappropriate and hostile” signal to Pyongyang, which has consistently condemned the joint drills in its backyard.

Ahead of the joint drills, the North responded by launching two ballistic missiles into the sea.

South Korean foreign minister Cho Hyun informed a parliamentary hearing that officers from South Korean and the US were not made aware of Mr Trump’s move.

Ulchi Freedom Shield is largely a computer-simulated command post exercise meant to hone the allies’ ability to deal with potential North Korean aggression. The two countries usually hold a set of field training exercises during the command post exercise period.

The drills and a similar springtime exercise are a central pillar of the US-South Korea alliance, dating back to the 1950s Korean War, which ended in an armistice rather than a peace treaty.

Since then, South Korea has been home to Camp Humphreys, the largest US military base outside the Americas. It is reportedly the first time when a US-South Korean drill has been cut short while it was underway instead of cuts being pre-decided.

A reduction or suspension of military drills matters because military commanders change periodically and one-year suspension of drills would mean commanders unfamiliar with the procedures of the drills would be taking part when they resume, according to Yang Uk, an analyst at Seoul’s Asan Institute for Policy Studies.

The North denounced the drills again on Wednesday, saying it would continue exercising its right to self-defence ⁠against what it called military threats from Washington and Seoul, the official news agency KCNA said.

It called the US and South Korea “warmongers” raising tension on the Korean peninsula, but stopped short of mentioning Mr Trump, his order or the scaling back.

Mr Trump has pushed aides to arrange an in-person meeting with the North’s leader as soon as this autumn, the Wall Street Journal reported. He has discussed holding talks during a possible November trip to Asia for ‌the Asia-Pacific Economic Cooperation summit in the Chinese technology hub of Shenzhen, the paper added.

The US president on Monday posted an edited picture of Mr Kim speaking to him on the phone and saying, “Hey Donald, We Cool… Right?”

Many experts said Mr Kim, now emboldened by his advancing nuclear programme and expanding military cooperation with Russia, won’t likely embrace Mr Trump’s overture anytime soon unless he’s promised bigger concessions.

In response to Mr Trump’s previous outreach, Mr Kim suggested last year that he can return to talks only after the US drops its demand for North Korean denuclearisation as a precondition for diplomacy.

Both leaders met three times from 2018-2019 but their high-stakes diplomacy eventually fell apart over wrangling over a North Korean demand for extensive sanctions relief in return for limited denuclearisation steps.

On Monday, the office of South Korean president Lee Jae Myung expressed hopes that a “friendly relationship” between Trump and Kim would lead to “meaningful dialogue” between their countries to promote peace on the Korean Peninsula.