The Associated Press
Thursday, March 24, 2011; 4:37 AM
The army says about 1,100 troops, dozens of artillery systems, attack helicopters and fighter jets participated in Thursday's drills.
Army officials say they mobilized more troops and weapons for the routine drills in a show of force two days before the country marks the anniversary of the warship Cheonan's sinking.
South Korea blames North Korea for torpedoing the vessel and killing 46 sailors. Pyongyang denies involvement.
North Korea shelled a South Korean island in November, killing four people and plunging inter-Korean ties to one of their lowest points in decades.