The United States and South Korea have started their regular joint military exercise, simulating emergencies on the Korean Peninsula.

Known as "The Freedom Shield," the exercise began in South Korea on Monday and will continue for 11 days through March 14.

The program is scheduled to involve 48 field training drills -- roughly twice the number of those conducted in the spring of last year.

They include bombing, live-fire shooting and intercepting cruise missiles. The two countries say the drills are designed to deal with a nuclear threat from North Korea.

South Korea's Yonhap News Agency reports that the US military may deploy strategic arms, such as a nuclear-powered aircraft carrier and a strategic bomber, to the Korean Peninsula during the drills. North Korea strongly opposes the deployment.

North Korean leader Kim Jong Un has stressed that he sees South Korea not as a counterpart for unification but as a foe. He said in an address in February that it is a national policy to occupy South Korean territory in the event of war.

During the Freedom Shield exercise a year earlier, North Korea fired an ICBM-class Hwasong-17 missile and several short-range ballistic missiles.

Observers say that in response to this year's drills, North Korea may launch missiles that are designed to carry nuclear warheads.