North Korea leader Kim Jong-un has promised to "buildup" the country's nuclear and missile weapons capabilities as a signal to the U.S.
"Our foreign political activities should be focused and redirected on subduing the U.S. - our biggest enemy and main obstacle to our innovative development," Kim said.
"No matter who is in power in the U.S., the true nature of the U.S. and its fundamental policies toward North Korea never change."
Separately, China President Xi Xinping offered Kim congratulations for his election this week as the general secretary of the communist Workers' Party of Korea.
Kim promised to expand ties with "anti-imperialist, independent forces" - a reference to China and Russia which support the country diplomatically and financially He did, however, reassure the world North Korea won't "misuse" its nuclear weapons.
Kim met outgoing U.S. President Donald Trump twice, in 2018 in Singapore and 2019 in Hanoi, for peace talks. The two failed to reach agreements to ease tensions along the world's most heavily armed cease fire line dividing North and South Korea in place since July 1953.
Kim, the third member of his family to lead the country after his father and grandfather, "has gloriously realized the historic mission to complete the country's nuclear build up," state-owned Korean Central News Agency said.
Kim said research on a nuclear ballistic missile submarine is nearly complete. South Korea claims its neighbor is building two submarines - one of which will be capable of deploying ballistic missiles. In late 2019 North Korea said it successfully tested a missile from the sea.
