A nuclear-powered American aircraft carrier has docked in South Korea for trilateral exercises, enhancing military collaboration just days following the signing of a mutual defense pact by North Korea and Russia.

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

"This arrival highlights the robust combined defense posture of the South Korea-US alliance and their determined resolve to address the mounting threats from North Korea," it was stated on Saturday.

The aircraft carrier is slated to engage in joint exercises with South Korea and Japan within this month. Pyongyang has consistently condemned such joint drills, labeling them as invasion rehearsals.

During a summit in August 2023, the leaders of these three nations concurred on conducting annual military training sessions. Earlier in the month, their defense chiefs outlined new exercises to hone their collective response across air, sea, and cyberspace.

The USS Theodore Roosevelt's deployment follows South Korea summoning the Russian ambassador to express objections to the recently established pact between Russian President Vladimir Putin and North Korean leader Kim Jong Un, which promises mutual defense aid in the event of conflict.

This marked Putin's first visit to North Korea in 24 years.

South Korea has stated that the deal between the two reclusive countries threatens its security and suggested it might consider dispatching weapons to Ukraine to counter the Russian invasion as a response.

Additionally, North Korean troops have been observed engaging in activities like laying more landmines, reinforcing tactical routes, and setting up what seem to be antitank barriers along the border, according to the South Korean military.

The two Koreas continue to be involved in a balloon warfare, with a South Korean activist confirming the launch of more balloons loaded with propaganda towards the North on Friday.

North Korea has already sent over a thousand balloons filled with trash to the South, with Kim Jong Un's influential sister, Kim Yo Jong, cautioning on Friday that the North might retaliate further.