Pyongyang denies carrying out cyberattack on South Korean officials' smartphones.
US official believes that the boat has sunk but Pyongyang has not mentioned the disappearance.
North Korean leader exhorts Pyongyang's scientists to bolster nuclear attack capability.
Concern grows over North Korea's activities as missile tests follow 'miniature nuke' claim.
For the first time Kim directly comments on Pyongyang's abilities to miniaturise nuclear warheads.
North Korean hackers pick up data from smartphones of top South Korean officials in high-profile cyber attack.
All of Pyongyang's projectiles fell into the sea but Seoul said it was keeping a close watch.
The decision comes two months after the country claimed it carried out a successful hydrogen bomb test.
UN Security Council postpones voting by 24 hours after Russia asks for more time to closely study sanctions.
Russia expressed concerns that harsher sanctions may affect North Korean people instead of Kim Jong-un regime.
Pyongyang claims student was promised a used car worth £7,200 to smuggle a propaganda sign out of the country.
The US calls the draft resolution the toughest sanctions against Pyongyang in more than two decades.
Washington and Beijing to prepare draft resolution calling for harsh UN sanctions on Pyongyang.
Security firms Symantec and AlienVault aim to combat hacking group thought to be responsible for Sony hack.
Wang Yi and John Kerry signal broader consensus on imposing harsh sanctions on Pyongyang.
US State Department confirmed negotiations with North Korea and said Pyongyang 'had called for the peace talks'.
South Korea urged North Korea to stop its 'vulgar' personal attacks on the president.
Kim Jong-un appoints his fourth military chief of staff since 2011 after predecessor is accused of sedition.
Pyongyang holds military exercises amid tensions in the Korean peninsula.
Seoul braces for GPS disruption during its joint military exercises Key Resolve and Foal Eagle with the US.
President Barack Obama signs legislation imposing fresh sanctions on Kim Jong-un's regime in Pyongyang.
South Korea expects possible cyberattacks, kidnappings, and poisoning attacks from Pyongyang.