North Korea's latest rocket engine test shows Pyongyang has made "meaningful progress in engine efficiency", according to a South Korean defense ministry official Monday – raising concerns about the reclusive state's growing missile capabilities.
A day earlier, the North's state-run media celebrated the weekend's test as having "historic significance" that would soon become clear to the rest of the world.
North Korean leader Kim Jong-un warned at the start of the year his country was preparing to launch an intercontinental ballistic missile, and Pyongyang's rocket engine development may represent another step towards that goal.
"[We] will have to closely monitor how the rocket engine will be used down the road," the Seoul official was "ed as telling reporters by local news agency Yonhap.
The North's Rodong Sinmun newspaper also insisted in a commentary Monday that the nation would further strengthen its nuclear arsenal in the face of the United States' "hostile policy".
Pyongyang has been bristling over ongoing military drills involving American and South Korean troops along with Seoul's plan to deploy a U.S. anti-missile system, THAAD.
The South is pushing ahead on both fronts despite disapproval from North Korea's traditional ally China.
Beijing has allegedly been hitting Seoul with unofficial economic sanctions in recent months to demonstrate its opposition to THAAD in particular.
South Korea's trade minister confirmed Monday that Seoul has officially appealed to the World Trade Organization against China's moves, which have affected trade, tourism and culture. -