North Korean leader Kim Jong Un has vowed to “indefinitely” pursue the development of nuclear weapons during a visit to two nuclear weapons facilities — a move seen as an implicit message to new U.S. President Donald Trump.

During Kim’s inspection of the country's Nuclear Weapons Institute and the unnamed facility for producing weapons-grade nuclear materials, the North Korean leader warned of an "inevitable" confrontation with hostile nations — a veiled reference to the U.S. — and called 2025 “a crucial year” for bolstering the country’s nuclear forces, the official Korean Central News Agency reported Wednesday without specifying the visit’s date.

Photos accompanying the report showed the North Korean leader walking with other officials in a massive hall containing row after row of centrifuges believed to enrich uranium by spinning it at high speeds.