South Korea has deployed five extra anti-submarine patrol aircraft to guard against a potential attack by North Korea. JoongAng Ilbo newspaper reported today that the military on Saturday deployed five P-3CK surveillance aircraft in addition to 11 anti-submarine planes already in operation to patrol the sea off the west and east coasts. The newspaper reported, cross-border military tension has soared after Pyongyang's shelling of the border island of Yeonpyeong on the Yellow Sea in late November, which killed four South Koreans including two civilians.