SEOUL, Nov. 26 (Yonhap) -- The series of explosion sounds heard Friday on the border island attacked by North Korea earlier this week appear related to training within the North's territory, military officials said.

   No shells landed in waters on either side of the Koreas' Yellow Sea border or near Yeonpyeong Island, said Col. Lee Bung-woo, a spokesman at the South's Joint Chiefs of Staff.

   "The firing was not aimed at us, and we believe the sounds were heard as North Korea conducted its routine training within its territory," Lee told reporters.

   There were sounds of about six explosions heard intermittently between 12:20 p.m. and a little past 3 p.m., he said.

   South Korea's military is on top alert after four people, two marines and two civilians, were killed on Yeonpyeong in the artillery attack by the North on Tuesday afternoon. Eighteen others, mostly marines, were injured, and fire gutted dozens of homes and buildings.

   The mere dozens of remaining residents on Yeonpyeong -- most evacuated earlier in the week to the mainland -- fled to shelters at the sound of the explosions. Local officials said main roads have been blocked.

   kdh@yna.co.kr
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