A report about Kim's visit to a chemical institute came not long after US Secretary of State Rex Tillerson appeared to make a peace overture to Pyongyang, welcoming what he called the recent restraint shown by the reclusive North.
Kim was briefed about the process of manufacturing intercontinental ballistic missile warhead tips and solid-fuel rocket engine during his tour of the Chemical Material Institute of the Academy of Defence Science, the North's official KCNA news agency said.
"He instructed the institute to produce more solid-fuel rocket engines and rocket warhead tips by further expanding engine production process and the production capacity of rocket warhead tips and engine jets by carbon/carbon compound material," KCNA said.