SEOUL - South Korean and US forces wrapped up a joint annual exercise aimed at enhancing defense readiness against potential security threats, the Combined Forces Command (CFC) said Friday.

The computer-assisted simulation exercise, dubbed Ulchi Freedom Guardian (UFG), was focused on combined planning, military intelligence, logistics and command and control operations, according to the CFC.

Launched on Aug 20, the drill, which officials said was defensive in nature, mobilized more than 56,000 South Korean and 30,000 US troops for operations at various sites nationwide.

"The exercise was based on realistic scenarios that enabled us to provide valuable training on our essential tasks and ensured we are fully prepared to defend the Republic of Korea," Gen. James D. Thurman, commander of the US forces stationed here, said in a statement.

Observers from seven countries including Australia, Canada and the United Kingdom participated in the drill to ensure it abided by the Armistice Agreement that halted the 1950-53 Korean War.

The Democratic People's Republic of Korea has repeatedly condemned joint drills by the allies as preparation for a northward invasion.