North Korea has criticized an agreement between the United States, South Korea and Japan to strengthen military cooperation -- claiming it is part of a US plan to create a military alliance like NATO in the region.

North Korea's foreign ministry spokesperson said as much to a question put by KCNA, the state news agency reported on Sunday.

“The reality clearly shows that the real purpose of the US spreading the rumor about a 'threat from North Korea' is to provide an excuse for attaining military supremacy over the Asia-Pacific region,” said the spokesperson.

“The prevailing situation more urgently calls for building up the country's defenses to actively cope with the rapid aggravation of the security environment,” the spokesperson added.

US President Joe Biden, Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk-yeol met on the sidelines of a NATO summit last week and agreed that the progress of North Korea's nuclear and missile programs posed serious threats to not only the Korean peninsula but also East Asia and the world.

They said they would explore further means to reinforce “extended deterrence” against North Korea.

North Korea has this year been conducting missile tests at an unprecedented pace, and is believed by some to be preparing for another nuclear test.

“The deterrence capabilities of the Japan-US and US-Republic Of Korea alliances need to be upgraded as part of the essential effort to strengthen the trilateral partnership between Japan, the US, and ROK,” Kishida said.

Ties between Japan and South Korea have long been strained by memories of Japan's occupation of the Korean Peninsula from 1910 to 1945.

Relations deteriorated to their worst in years under South Korea's previous President Moon Jae-in, with spats over territory and history and the two nations calling off an intelligence sharing pact. Yoon, though, has expressed a desire to repair ties, and Kishida has also seemed to respond favorably. (CNN)