 Complete the following phrase:  On 21 May 2013, Uriminzokkiri claimed that North Koreas threat to target Cheong Wa Dae using unmanned aerial vehicles instead of surface-to-surface missiles was intended to use terrain features for cover. It also pointed out that the UAVs are capable of hitting Cheong Wa Dae in less than three minutes travelling at 925 kmh. The website further boasted that North Korean drones are also capable of attacking the Capital Defence Command on the southern side of Mount Kwanak in southern Seoul. South Koreas top brass ignored these imminent provocations, just as they did in 2010 before the sinking of the 