SEOUL (Reuters) - North Korea launched an unknown ballistic missile toward the sea to the east coast of the Korean Peninsula, South Korean military said on Wednesday.

Japan's coast guard said a projectile believed to be the North Korean ballistic missile appeared to have already fallen.

North Korea earlier this week criticised the deployment of a U.S. aircraft carrier to join joint drills with South Korea and Japan, and warned of "overwhelming, new demonstration of deterrence".

The nuclear-powered U.S. aircraft carrier, the Theodore Roosevelt, arrived in the South Korean port city of Busan on Saturday to take part in joint military exercises later this month with the host nation and Japan, naval officials said.

The missile launch comes a day after the 74-year anniversary of the beginning of the Korean War.

Recently, North Korea has been flying hundreds of balloons carrying trash toward the South including on Tuesday, while Pyongyang deployed a large squad of soldiers to build new fortifications within the heavily armed border between the two Koreas according to the South's military, occasionally inviting warning shots from South Korean counterparts.

(Reporting by Joyce Lee; Editing by Chris Reese and Sandra Maler)

By Joyce Lee