The North Korean military moved a battalion of 122-mm multiple rocket launchers from the Fourth Corps to a coastal artillery base in Kaemori in Kangryong, South Hwanghae Province just before shelling Yeonpyeong Island on Tuesday, but despite detecting the move in advance, the South Korean military fired back at the base along the shoreline in Mudo, not Kaemori. This raises concerns about the ability of the military to deal with attacks.

A senior military said several hours before the shelling began the North Korean military deployed one battery of six 122-mm MRLs and later two batteries of 12 112-mm MRLs. It also carried out preparatory shooting practice just before the attack. "As far as I know the South Korean military was aware of this," he said.

The 122-mm MRLs are not stationed at the North's coastal artillery bases and had to be moved to Kaemori, so the activity should have put the South Korean military on high alert.