A North Korean propaganda channel has published a video showing a missile allegedly targeting the U.S. territory of Guam in the northwestern Pacific.
The footage was released just days after Pyongyang carried out a test launch of Musudan missiles theoretically capable of flying more than 1,800 miles.
South Korean and U.S. officials said the first rocket failed over the Sea of Japan but a second missile was test-fired hours later, and reportedly flew for 248 miles before it fell.
It comes as the United States, Japan and South Korea held their first trilateral missile defence drill off Hawaii.
Officials said the exercise, dubbed "Pacific Dragon", was aimed at countering the growing nuclear threat from North Korea.
The drill included a ballistic target tracking operation to test the Aegis anti-missile systems used by the U.S. and its two key Asian allies.
"While there were no missiles fired, all participants strengthened interoperability, communication channels, data collection, and capabilities assessments," the U.S. Pacific Command said in a statement.
Vice Admiral Nora Tyson, commander of the U.S. Third Fleet, said as well as rehearsing responses to a North Korean missile attack, the exercise "enhanced the already strong relationship of all three nations participating".
North Korea's foreign ministry condemned it as "another military provocation perpetrated by the U.S." and reiterated strategic willingness to carry out a "pre-emptive nuclear attack" if threatened.
The participation of all three countries revealed their "hegemonic scenario for disturbing regional peace and security,” a ministry spokesman was quoted as saying by the official KCNA news agency.
The North has this year claimed a series of major technical breakthroughs in developing what it sees as the ultimate goal of its nuclear drive: an intercontinental ballistic missile (ICBM) capable of delivering a nuclear warhead to the U.S. mainland.
The recent test of the Musudan medium-range missile was seen by some weapons experts as a significant step towards an operational ICBM by 2020.