A US aircraft carrier arrived in South Korea on Saturday for a joint military drills aimed to better counter North Korean threats, Seoul's navy said.

"The US Navy's aircraft carrier Theodore Roosevelt... arrived at the Busan Naval Base on the morning of June 22," the South Korean Navy said in a statement.

Its arrival "demonstrates the strong combined defence posture of the South Korea-US alliance and their firm resolve to respond to the escalating threats from North Korea," it added.

The carrier's visit comes around seven months after another US aircraft carrier, the USS Carl Vinson, came to the South in a show of strength against Pyongyang.

The USS Theodore Roosevelt is expected to participate in joint exercises with South Korea and Japan this month. Pyongyang has always decried similar combined drills as rehearsals for an invasion.