AKIPRESS.COM - North Korea said Wednesday its latest ballistic missile tests were personally ordered and monitored by supreme leader Kim Jong-un and simulated nuclear strikes on U.S. bases in South Korea, said Al Jazeera.

The three missiles launched on Tuesday were a dry run for attacks on South Korean ports and airfields hosting U.S. military "hardware", according to the North's official KCNA news agency.

The tests "examined the operational features of the detonating devices of nuclear warheads mounted on the ballistic rockets at the designated altitude over the target area," it said.

North Korea fired three ballistic missiles that flew between 500 km and 600 km into the sea off its east coast, South Korea's military said.

The U.S. military said it believed two of the missiles were Scuds and the other a Rodong, a home-grown missile based on Soviet-era Scud technology.

North Korea is believed to be developing nuclear warheads and trying to miniaturize them to mount on ballistic missiles, but some experts say it may be a few years away from mastering the technology.

But Tuesday's missile launches were seen as a show of force rather than a test to improve missile capabilities, a week after South Korea and the United States chose a site in the South to deploy the Terminal High Altitude Area Defense (THAAD) anti-missile system to counter threats from the North.

UN Secretary General Ban Ki-moon on Tuesday said the tests were "deeply troubling" and undermined efforts to reduce tension on the Korean peninsula.