The South Korean navy's air cushion landing craft approaching the beach as a US Marine took his position during the US-South Korea joint landing military exercises as a part of the annual joint military exercise Foal Eagle between South Korea and the US in Pohang, south of Seoul, South Korea, on Monday. Lee Jin-man/AP Operation Foal Eagle 2015, which runs from March 2 to April 24, features US and South Korean Marines practicing amphibious beach assaults along with aerial and naval operations.

The operation involves 12,500 US troops, along with an astonishing 200,000 of their South Korean counterparts.

Because Foal Eagle takes place in South Korea, North Korea views it as a possible practice run for an invasion. Pyongyang has ratcheted up the rhetoric and has threatened that Foal Eagle 2015 would be greeted with a "merciless baptism by fire."

In response to the start of Foal Eagle, North Korea launched two SCUD missiles into the sea outside of South Korea on March 2. On March 12, North Korea fired an additional seven surface-to-air missiles to protest against the exercise.