North Korea criticised a joint military exercise by South Korea, Japan and the United States held this month, state media said on Sunday, saying such drills show the relationship among three countries has developed into "the Asian version of NATO".

On Thursday, the three countries began large-scale joint military drills called "Freedom Edge" involving navy destroyers, fighter jets and the nuclear-powered U.S. aircraft carrier Theodore Roosevelt, aimed at boosting defences against missiles, submarines and air attacks.

The exercise was devised at the three-way summit at Camp David last year to strengthen military cooperation amid tensions on the Korean peninsula stemming from North Korea's weapons testing.

Pyongyang will not ignore the strengthening of a military bloc led by the U.S. and its allies and will protect regional peace with an aggressive and overwhelming response, North Korea's foreign ministry said in a statement, according to KCNA news agency.

The ministry also said Washington was continuing its effort to link up South Korea and Japan to the North Atlantic Treaty Organization (NATO), adding South Korea's attempts to supply weapons to Ukraine is one example of that effort.

Seoul's defence ministry said in a statement that the "Freedom Edge" exercise was in response to North Korea's nuclear and missile program while dismissing Pyongyang's criticism.

South Korea said it would review the possibility of supplying arms directly to Ukraine, in protest against a recent mutual defence pact signed between North Korean leader Kim Jong Un and Russian President Vladimir Putin.

South Korea and the United States have accused the North of supplying weapons to Russia that are being used in the Ukraine war. Both Russia and North Korea deny any such transactions.

North Korea's ruling party held a meeting over Friday and Saturday presided by Kim, who on the second day addressed "deviations" hampering economic development and laid out the focus for the second half of the year, state media said.

North Korea has long condemned joint drills between the United States and South Korea as a rehearsal for invasion and proof of hostile policies by Washington and Seoul.

Last year, the U.S., South Korea and Japan staged joint naval missile defence and anti-submarine exercises to improve responses to North Korean threats.