(Reuters) - North Korean leader Kim Jong Un has overseen drills simulating a nuclear counterattack against the U.S. and South Korea in a warning to the allies who are scaling up their joint military exercises, state media KCNA said on Monday.
The North's drills involved a short-range missile launch but - unusually - the missile flew from a buried silo, which analysts say would help improve speed and stability in future tests of intercontinental ballistic missiles (ICBM).
KCNA said the exercises on Saturday and Sunday were designed to boost the country's "war deterrence and nuclear counterattack capability," accusing Washington and Seoul of making an "explicit attempt to unleash a war" against it.
"The drill also aimed to demonstrate our tougher will to make an actual war response and send a stronger warning to the enemy who expand their war drills for aggression," KCNA said.
In the exercises, a ballistic missile equipped with a mock nuclear warhead flew 800 km (497 miles) before hitting a target under the scenario of a tactical nuclear attack, KCNA said.
KCNA photos showed Kim attended the test, again with his young daughter, as flames roared from the soaring missile before it hit the target.
Analysts said the photos suggested the launch involved a KN-23 short-range ballistic missile (SRBM), but unlike past tests, the engine exhaust appeared to be vented either side at the moment of liftoff, which could mean that a silo was used.
"Until now, North Korea has preferred mobile launchers for everything from SRBMs to even huge ICBMs, but given its poor road and system conditions, it was difficult to guarantee the stability of the missile during actual operations," said Yang Uk, a fellow at the Asan Institute for Policy Studies in Seoul. "The latest launch might possibly serve as a test for future launches of larger missiles like the Hwasong-17 ICBM in a silo."
South Korea's defence ministry spokesman said the North is making significant technological advances in its nuclear programme but did not elaborate.