Japan has no plans to sign a UN treaty banning nuclear weapons, the government's top spokesman said Monday, explaining that the country has a different approach. Japan's stance puts it in lockstep with the United States but could be seen as contradicting its anti-nuclear credo. "As the Treaty on the Prohibition of Nuclear Weapons is different from our approach, we will not sign the treaty. There is no change in our stance," Chief Secretary Katsunobu Kato told a news conference. "Although Japan shares the goal of abolishing nuclear weapons, it is appropriate to make steady and realistic efforts to advance nuclear disarmament while dealing appropriately with security threats, including maintaining and strengthening our deterrence," Kato said. "We believe, given the increasingly difficult security environment surrounding Japan, it is appropriate to make steady and realistic progress toward nuclear disarmament while maintaining and strengthening our deterrence capabilities to deal with threats," Kato added. "Japan shares the goal of this treaty, the abolition of nuclear weapons... but as we differ in how to approach the issue, we will not become a signatory," he said referring to the treaty. The UN announced on Saturday that the treaty is set to take effect on Jan. 22 after Honduras became the 50th country to ratify the pact. The global pact, which was approved by the 193-member UN General Assembly in 2017, requires all ratifying countries to "never under any circumstances develop, test, produce, manufacture, otherwise acquire, possess or stockpile nuclear weapons or other nuclear explosive devices." But the five major nuclear powers China, France, Russia, UK and the US, as well as other nuclear weapon states such as India, Pakistan, North Korea and Israel have not joined the treaty. As the only country to have suffered a nuclear attack, Japan has sought to paint itself as a leader in international efforts for nuclear disarmament and nonproliferation. But Japan also depends on the US nuclear umbrella to protect it from threats including North Korean missiles, preventing it from endorsing an all-out ban on the production, use and stockpiling of nuclear weapons. Asked if Japan would be willing to participate as an observer, Kato stressed the need for "careful consideration based on Japan's position." Survivors of the August 1945 US atomic bombings of Hiroshima and Nagasaki, which together killed an estimated 214,000 people by the end of that year, and other anti-nuclear activists have urged the administration of Prime Minister Yoshihide Suga to sign onto the historic but largely symbolic treaty. In Nagasaki, a digital clock erected in front of the city hall on Monday began the countdown to the treaty's entry into force. "There is only one path Nagasaki is pursuing, and that is the one that leads to realizing a world without nuclear weapons," Mayor Tomihisa Taue said at an unveiling ceremony. Around 50 activists marched through central Hiroshima carrying large banners and signs calling for Japan to join the treaty, which was adopted in July 2017 with the support of 122 countries and regions. Kunihiko Sakuma, the head of a group supporting survivors and himself an A-bomb victim, said he was confident the world was moving toward abolishing nuclear weapons. "We won't give up," the 76-year old said. — KUNA/Kyodo