SEOUL (Reuters) - Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, again denied arms exchanges with Russia, state media KCNA reported on Friday.

The U.S. and South Korea accused North Korea of transferring weapons to Russia for use against Ukraine, which it invaded in February 2022. Both Moscow and Pyongyang have denied the accusations, but vowed last year to deepen military relations.

Ties between the two countries have strengthened dramatically following North Korean leader Kim Jong Un's visit to Russia's far east in September and a summit with President Vladimir Putin.

But, Kim Yo Jong said the North Korea-Russia arms deal "theory" made up of prejudice and fiction was the "most absurd theory" that does not deserve anyone's evaluation or interpretation, according to KCNA quoting her press statement, calling it a false rumour spread by its hostile forces.

Kim Yo Jong added North Korea's developing weapons were not meant for exports but for defence against South Korea

North and South Korea remain technically at war because their 1950 to 1953 conflict ended in a truce, not a treaty.

Meanwhile, the United States announced fresh sanctions on Thursday on two Russian individuals and three Russian companies for facilitating arms transfers between Russia and North Korea, including ballistic missiles for use in Ukraine.

The debris from a missile that landed in the Ukrainian city of Kharkiv on Jan. 2 was from a North Korean Hwasong-11 series ballistic missile, United Nations sanctions monitors told a Security Council committee in a report seen by Reuters.

Amid a growing partnership between Moscow and Pyongyang, North Korea's ambassador to Russia on Thursday called Ukrainian President Volodymyr Zelenskiy a U.S. puppet, and said Russia would emerge victorious in its conflict with Kyiv, KCNA reported.

(Reporting by Ju-min Park and Josh Smith; Editing by Chris Reese and Jamie Freed)