US nuclear-powered aircraft carrier is escorted as it arrives in Busan, South Korea, on Thursday. AP

A US nuclear-powered aircraft carrier arrived in South Korea on Thursday in a demonstration of strength against North Korea, as the North’s leader reaffirmed his push to bolster ties with Russia.

The USS Ronald Reagan and its battle group came to the southeastern South Korean port of Busan after participating in a trilateral South Korean-US-Japanese maritime exercise in international waters off a southern South Korean island earlier this week, the South Korean Defense Ministry said.

The aircraft carrier is to stay in Busan until next Monday as part of a bilateral agreement to enhance "regular visibility” of US strategic assets to the Korean Peninsula in response to North Korea’s advancing nuclear program, according to an earlier Defence Ministry statement.

Many experts say Kim would want Russian help to build more reliable weapons systems targeting the US and South Korea. Washington and Seoul have warned that Moscow and Pyongyang would pay a price if they move ahead with the speculated weapons transfer deal in breach of UN Security Council resolutions that ban any weapons trading with North Korea.

On Thursday, Kim and Putin exchanged messages marking 75 years of diplomatic ties between the two countries.

In his message to Putin, Kim said he was "very satisfied” over "an exchange of candid and comprehensive opinions” with Putin during his Russia trip, while expressing a firm belief that bilateral ties will develop onto a new level. Kim also hoped that the Russian people would defeat "the imperialists’ persistent hegemonic policy and moves to isolate and stifle Russia,” according to the official Korean Central News Agency.

Putin, for his part, told Kim in his message that he was satisfied with the fact that bilateral ties continue to positively develop in all aspects, KCNA said.

Associated Press