SEOUL, June 27 (Reuters) - North Korea has accused the United States of setting up a military alliance like the North Atlantic Treaty Organization (NATO) in Asia, saying that the unwavering US aim to oust North Korea's government compelled it to develop stronger defences.

The North Korean criticism comes amid concern that it could be preparing its first nuclear test in five years and after a recent agreement between South Korean President Yoon Suk-yeol and US President Joe Biden to deploy more US weapons if deemed necessary to deter the North.

"While blatantly holding joint military exercises with Japan and South Korea, the United States is making a full-fledged move to establish an Asia-style NATO," North Korea's foreign ministry said in a statement on its website on Sunday (Jun 26).

It was referring to recent military exercises conducted by US, South Korean and Japanese forces. The United States also held exercises with South Korean forces that involved a US aircraft carrier, for the first time in more than four years.

North Korea, which has been conducting regular missile tests this year, repeated its assertion that such drills were preparation for war aimed at overthrowing it.

"This proves the hypocrisy of the US rhetoric of 'diplomatic engagement' and 'dialogue without preconditions', while at the same time revealing again that there is no change in the US ambition to overthrow our system by force," the North Korean ministry said.

It did not refer explicitly to its nuclear or missile programmes but said that US hostility compelled it to develop its defences.

"The reality ... makes us feel the need to make all-out efforts to develop even stronger power to be able to subdue all kinds of hostile acts by the United States," it said.

The United States is insisting that North Korea give up its nuclear weapons and has repeatedly offered to meet North Korean officials "at any time without preconditions" to discuss the issue. North Korea has rebuffed the offers.

The North Korean criticism came a day before South Korea's president left to attend a NATO summit in Spain, the first South Korean leader to do so.

South Korea, aiming to strengthen its partnership with NATO and play a bigger global security role, plans to set up a delegation to NATO at its Brussels headquarters, South Korea's national security adviser said last week.