UNITED NATIONS, United States (AFP) - The UN Security Council will hold an emergency meeting on Wednesday (Aug 3) to discuss Pyongyang's launch of a ballistic missile that for the first time landed in Japanese-controlled waters.

The United States and Japan called for the urgent talks, which are to begin at 4pm (4am on Thursday, Singapore time).

North Korea fired two intermediate-range missiles simultaneously, but one appeared to explode on takeoff, according to the US military.

The second missile landed in the Sea of Japan (East Sea), some 250km off Japan's northern coast and within its Exclusive Economic Zone (EEZ).

UN Secretary-General Ban Ki-moon is "deeply troubled" by the latest test launch, his spokesman said, adding that "such actions seriously undermine regional peace and stability."

"We reiterate the call on the DPRK to heed the united call of the international community to reverse its course and return to the process of sincere dialogue," said UN spokesman Stephane Dujarric, using the initials for the Democratic People's Republic of Korea, the North's official name.

Britain's Deputy Ambassador Peter Wilson said: "This is the first time that a DPRK missile has landed in the Japanese EEZ. I think this is something that the council should take extremely seriously."

Wilson said the latest launch was "a clear violation of UN Security Council resolutions" that prohibit North Korea from developing missile technology.

The US Strategic Command said the two missiles were launched from a site in western North Korea around 7.50am Seoul time (6.50am on Wednesday, Singapore time).

The council has repeatedly condemned North Korea's missile launches, but a US-drafted statement circulated last month following an apparent submarine-launched missile test has bogged down in discussion with China, the North's closest ally.

On June 23, the council adopted a statement condemning North Korea for two medium-range missile tests.

North Korea has been hit by five sets of UN sanctions since it first tested an atomic device in 2006.

The council in March adopted its toughest sanctions resolution to date, banning exports of coal, iron and other minerals from North Korea and imposing other restrictions, in particular in the banking sector.