North Korea appears to be preparing to launch medium-range missiles following the firing of two short-range missiles into the East Sea on Monday.
 
A government source said Tuesday that signs have been detected over the past several days that the North has deployed two mobile launchers at a Rodong missile station in North Pyeongan Province. 
 
The source said that the South Korean military is keeping a close eye on the possible launch of medium-range ballistic missiles, noting that the North used mobile launchers when it fired the Rodong missiles last year.
 
The ministry and the Joint Chiefs of Staff are known to be operating their crisis management system over the prospect of additional provocations by North Korea. 
 
Defense ministry spokesman Kim Min-seok said in a regular briefing on Monday that Seoul is stepping up joint surveillance on North Korea in cooperation with the United States.