North Korean leader Kim Jong-un orders more warheads, rockets

North Korean leader Kim Jong-un has demanded an increase in the production of rocket warhead tips and engines, Pyongyang's state media said Wednesday.

The call came as tensions between the pariah state and the U.S. appeared to dissipate.

A report by the North's Korean Central News Agency (KCNA) on a visit to a chemical institute said Kim had "instructed the institute to produce more solid-fuel rocket engines and rocket warhead tips".

However, the report lacked the usual anti-U.S. rhetoric and followed U.S. Secretary of State Rex Tillerson's remarks in which he welcomed recent restraint by Pyongyang.

His comments followed weeks of ratcheting tension, with U.S. President Donald Trump suggesting military action against the North.

The Rodong Sinmun newspaper carried a photograph of Kim smiling broadly during an inspection of the chemical institute, where he was briefed on the manufacture of intercontinental ballistic missile (ICBM) warheads and rocket engines, KCNA reported.

North Korea conducted two ICBM tests last month, which resulted in fresh sanctions, as well as dozens of other missile tests and two nuclear tests since the start of 2016.

Despite the ICBM tests, the last of which appeared to be able to reach the continental U.S., analysts remain split on whether Pyongyang has warheads capable of withstanding the immense heat of atmospheric re-entry.

Building more solid-fuel engines, which require little preparation to launch, could increase the North's capacity to stage a surprise attack.

Another application of the North's growing weapons technology would be submarine-launched ballistic missiles.

On Wednesday, sirens sounded to simulate an air attack across South Korea as the annual U.S.-South Korean military exercise incorporated civilian drills that saw traffic come to a halt and people seek shelter.

Meanwhile, President Moon Jae-in visited a command center and asked commanders for "complete defense readiness" in case of North Korean provocation, his spokesman said.

The North has refused to accept Moon's offers of dialogue since he took office in May, claiming Seoul lacks sincerity in view of its pressure for further sanctions on Pyongyang.