The South Korean and U.S. militaries remain on alert for signs of provocation by North Korea as it approaches an important anniversary.
 
Tuesday marks the 72nd anniversary of the ruling socialist party’s founding, and Pyongyang has used similar occasions in the past to demonstrate military capabilities.
 
A South Korean defense official says the military is prepared respond to any contingency.
 
South Korea and the U.S. are boosting their surveillance of the North with advanced hardware such as the Lockheed U-2S ultra-high altitude reconnaissance aircraft, E-737 airborne early warning and control aircraft and P-3C maritime patrol aircraft.
 
In the East Sea, Aegis destroyers equipped with radars that can detect North Korea ballistic missiles have been deployed. On the ground, the Green Pine ground-based missile-defense radar is also in operation.