North Korea threatened to make Japan “regret” its ongoing military build-up, warning that it would consider options after Tokyo test-fired a US-made Tomahawk cruise missile.Kim Yo Jong, the sister of North Korean leader Kim Jong Un, accused Japan of transforming into a war state with American support and abandoning its constitutionally mandated pacifist posture, the state-controlled KCNA news agency reported.Since Sanae Takaichi took over as prime minister last year, Japan has increased defence spending, easing arms export restrictions, and strengthening regional security ties. It has also deployed missile launchers to its outer islands.The Takaichi government is even considering a revision of Article 9 of the constitution, the centrepiece of Japan’s post-war pacifism which renounces war and states that the country, which was on the losing side in World War II, will not maintain military forces for the purpose of settling international disputes.Japan’s defence minister said on Tuesday that the country needed to boost its defence “with a sense of urgency and crisis" after his ministry released its annual White Paper assessment that flagged growing threats from China, Russia, and North Korea.Analysts say Pyongyang is seeking to ​portray Japan's military modernisation as a direct security threat to justify its own weapons ‌development.Ms Kim, who heads the recordkeeping department of the ruling Workers’ Party of Korea, denounced Japan for test-firing the Tomahawk long-range cruise missile and participating in US-led military drills in the Philippines.Japanese prime minister Sanae Takaichi holds a press conference in Tokyo (Reuters)She said the testing of the missile placed Japan’s neighbours, including North Korea, within range.She alleged that Japan was moving “to formulate the possession of the capability for pre-emptive attack" and warned that Pyongyang would “make Japan feel that its security has been exposed to greater danger due to its greediness”. “We should make it regret,” she said.Japan had thus far behaved as a peace-loving state in the eyes of the international community, Ms Kim said, but it was now “clear that such moves were, after all, a camouflaged tactic to cover up its ambition for a military giant”.Japan test-fired the Tomahawk from a warship last week as part of its new military strategy to deploy weapons capable of hitting enemy targets from long range amid rising tensions with China and North Korea. The Tomahawk, which flies at a low altitude to evade radar detection, is a major component of this strategy. Japan has agreed a deal to buy 400 Tomahawks from the US by March 2028.Yang Moo Jin, professor at the University ⁠of North Korean Studies in Seoul, said Ms Kim's comments were an attempt to frame Tokyo's steps ⁠as part of a broader US effort to strengthen its proxy military capabilities to counter North Korea.The messaging could ‌lay the groundwork for ​future military demonstrations by Pyongyang, including missile tests or displays ‌of undersea strike capabilities, Lim Eul chul, ​professor at the Institute for Far Eastern Studies, Kyungnam University, said.