The United States wants to wrap up discussions with South Korea on the deployment of a sophisticated defense system, the Pentagon said Friday, two days after North Korea's latest missile tests.

Seoul and Washington have for weeks been in talks about deploying the advanced US THAAD missile system in South Korea to protect against the potential threat from Pyongyang -- a move vehemently opposed by China.

"We would like to see these conversations, as I think the South Koreans would, wrapped up in an as efficient and timely fashion as possible," Pentagon press secretary Peter Cook said.

He said discussions had "progressed well," but there were still "some details to work out."

North Korea tested two Musudan medium-range missiles just hours apart on Wednesday.

The first was seen as a failure, but leader Kim Jong-Un hailed the second as a complete success.

South Korea has had reservations about THAAD -- the Terminal High Altitude Area Defense System -- primarily because of opposition from China, which sees it as a threat to its own nuclear deterrent.

Beijing also fears the presence of more US military hardware on its doorstep will further tip the balance of power in the Pacific towards Washington.

Pentagon officials spoke with South Korean and Japanese counterparts earlier on Friday to discuss the recent North Korean missile launches, Cook said.

"All three countries reiterated their strong condemnation of these launches and urged North Korea to refrain from provocative actions that undermine peace and security and instead focus on fulfilling its international obligations and commitments," he told reporters.

"The three noted that North Korea's provocations would only strengthen the resolve of the international community."

N. Korea rejects UN rebuke, warns tensions 'uncontrollable'
Seoul (AFP) June 24, 2016 - Pyongyang on Saturday rejected the UN Security Council's sharp criticism of its latest missile tests and blamed the United States for driving the divided peninsula toward an "uncontrollable extreme phase".

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.

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.