A Musudan missile is launched from North Korea's Wonsan city (Photo: Yonhap/VNA)

The official said that transporter vehicles carrying ballistic missile launching equipment were seen arriving in Kusong, North Korea, on Friday. A launch could occur within 6 days, possibly coinciding with an upcoming North Korean holiday on Thursday celebrating the armistice which ended the Korean War.

CNN quoted a US intelligence source as saying that North Korea is preparing for another intercontinental ballistic missile  (ICBM) or intermediate range missile test.