North Korea this week conducted its most successful tests to date of a powerful home-grown missile it hopes will one day be capable of launching nuclear attacks on the US mainland.
They drew a strong rebuke from the UN Security Council, which described the launches as "grave violations" of resolutions banning the North from developing ballistic missiles.
The 15-member council called for sanctions to be redoubled after holding an emergency meeting over the tests.
But Pyongyang rejected the criticism, calling it "a product of high-handedness wantonly violating the sovereignty of an independent state".
"This is an unreasonable deed of turning black into white," a foreign ministry spokesman said in a statement carried by state news agency KCNA.
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North Korea has conducted a string of failed missile launches this year which, coming hot on the heels of its fourth nuclear test in January, have escalated international tensions.
At a rare congress of the ruling party in May, leader Kim Jong-Un vowed Pyongyang would push ahead with its nuclear weapons programme despite UN sanctions and near universal condemnation.
North and South Korea have technically been at war for decades, and Seoul has rejected recent overtures for peace talks with Pyongyang as an "insincere" propaganda ploy.
Saturday's KCNA statement blamed the US for ratcheting up tensions between the neighbours by sending weapons to South Korea.
"Its (the US's) sustained strategic mistake and rash deed are now driving the situation on the Korean peninsula to the uncontrollable extreme phase," it warned.
