North Korean leader Kim Jong Un said his country will unveil plans to further bolster its nuclear programme at the upcoming ruling party congress, as he observed the North's latest weapons launch, state media reported Wednesday. The report came a day after South Korea and Japan said they detected multiple ballistic missiles fired from North Korea, the country's first weapons launches in about three weeks. The Korean Central News Agency said North Korea performed a live-fire drill of an upgraded large-caliber multiple rocket launcher system in the presence of Kim on Tuesday.

It quoted Kim as saying the test launch was meant to enhance the effectiveness of the country's "strategic deterrent," a term used to describe its nuclear weapons capability. KCNA said the launcher system's mobility and strike accuracy have been improved. Experts say North Korea's large-sized rocket launchers blur the boundaries between artillery systems and ballistic missiles because they can create their own thrust and are guided during delivery.