US, South Korea postpone joint exercise criticised by North

South Korean President Moon Jae-in with US President Donald Trump (AP Photo/Manuel Balce Ceneta/ File)

The United States and South Korea on Sunday said they were postponing a joint military air exercise that North Korea has criticised as provocative.

US Defense Secretary Mark Esper and his South Korean counterpart made the announcement in Bangkok, where they were attending an Asia defence ministers conference.

As recently as Friday, when Esper was in Seoul to consult with South Korean officials, there was no word on postponing the military air exercise, which had been called Vigilant Ace.

Seoul and Washington had scaled back the exercise recently and changed the name, but North Korea strongly objected, calling it evidence of a lack of interest in improving relations.

The North has demanded accommodations before it will agree to resume nuclear negotiations.

South Korean Defense Minister Jeong Kyeong-doo said the exercise had been put off pending further consultations between Seoul and Washington. No new date has been set.

Esper told reporters he did not consider the postponement a concession to North Korea.

"I see this as a good-faith effort by the United States and the Republic of Korea to enable peace ... to facilitate a political agreement, a deal if you will, that leads to the denuclearisation of the Korean Peninsula," Esper said.