North Korean leader Kim Jong Un said the development program his country’s nuclear weapons development programme will continue “indefinitely”, days after US President Donald Trump referred to a possible diplomatic opening towards Pyongyang.

After inspecting a nuclear materials production plant, Kim also spoke of an “inevitable” conflict with his country’s enemies, stressing that 2025 would be a “crucial year” for strengthening the country’s nuclear forces, according to state news agency KCNA.

“It is our firm political and military position and our sacred duty to unrestrictedly develop our state’s nuclear weapons retaliation capability,” the North Korean leader said, according to the agency.

The statements follow Pyongyang’s test of strategic sea-surface cruise missiles on Saturday, the first of its kind since Donald Trump’s return to the White House on January 20.

North Korea says it is developing a nuclear arsenal to counter threats from the US and its allies, particularly South Korea.

Relations between Pyongyang and Seoul are at their worst point in recent years. North Korea continued a series of intensive ballistic missile tests last year, defying a series of UN Security Council resolutions and sanctions.

Donald Trump, who had a series of – extremely rare – meetings with Kim Jong Un during his first term (2017-2021) as US president, said during an interview last week that he would seek to re-engage with the North Korean leader, whom he described as a “smart guy”.

Today, according to KCNA, the latter referred to the “most unstable situation in the world, during which long-term conflict with the most vicious hostile countries is inevitable” and, in this context, deemed it “necessary for the country to strengthen its nuclear shield.”