(VOVworld) - South Korea and the US conducted a joint naval drill on Friday ahead of the launch of large-scale military exercises next week that have incensed North Korea.

US submarine USS Olympia(SSN-717) mooring at a South Korean naval base in Changwon (Photo: AFP)

The drill involved 10 South Korean warships, backed by surveillance planes and helicopters, as well as the U.S. Aegis destroyer and Sea Hawk helicopters, a South Korean defense ministry spokesman said. The drill was a prelude to the eight-week annual Foal Eagle exercises, which kick off on Monday and involves air, ground and naval field training, with around 200,000 South Korean and 3,700 U.S. troops. A week-long, largely computer-simulated joint exercise, Key Resolve, also gets under way on Monday. The annual drills are a perennial source of tension on the divided Korean peninsula. Seoul and Washington insist they are defensive in nature, but they are regularly condemned by Pyongyang as provocative rehearsals for invasion.