The UN Secretary-General says the latest missile tests by the secretive state were "brazen and irresponsible"
Kim Jong-Un claims North Korea has the capability to strike US military bases across the Pacific following its latest test of a mid-range missile.
The leader was in attendance as Pyongyang launched two mid-range missiles, dubbed Musudan, off its eastern coast on Wednesday.
The first launch failed over the Sea of Japan, according to South Korean and US officials.
A second was test-fired hours later in the direction of Japan and reached a high altitude before it fell into the sea around 400 km away, according to the North's KCNA news agency.
"We have the sure capability to attack in an overall and practical way the Americans in the Pacific operation theatre," Kim was quoted as saying, as he applauded a "great event".
Images released by the secretive state showed a clearly elated leader watching the tests and celebrating with military officials.
In one photograph he could be seen hugging an official, while in another he appeared to be almost dancing with delight surrounded by his top guns.
The rockets have a range of around 3,000 km - so South Korea, Japan and the US territory of Guam are potentially within reach.
North Korea is banned from using any type of ballistic missile technology, but has regularly fired short-range rockets from its eastern coast.
Washington and Seoul condemned the move, while Japan described it as a "grave provocative action".
UN Secretary-General Ban Ki-moon said the tests were "brazen and irresponsible" as they triggered emergency UN Security Council talks on curbing Pyongyang's nuclear programme.
US Defence Secretary Ashton Carter urged the expansion of missile defence systems in the region.
"We need to stay ahead of the threat," he said.
Meanwhile, Japan has started its examination of the suspected nose cone of a North Korean rocket fired by Pyongyang on 7 February.
It washed up on a beach on its west coast and officials said they hoped analysis of the material would give them some idea of the level of technology used.