Japanese Prime Minister Shinzo Abe said on Thursday that the country was facing its greatest security threat since World War II because of North Korea’s missile development programme, The Japan Times reported. Abe said his administration would strive to improve Japan’s defences to protect the country’s citizens.

“We will go forth with resolute diplomacy in order to make North Korea change its policies,” Abe told a New Year press conference Ise, Mie Prefecture. “We will strive to strengthen our defences, not just as an extension of existing practices but in the way that is truly necessary to protect the citizens.”

“It is absolutely unacceptable that North Korea is trampling the strong desire of Japan and the rest of the international community for peaceful resolutions and continuing with its provocative behaviour,” the Japanese prime minister said, according to Reuters.

The prime minister added that he would “closely watch” the effect of United Nations’ sanctions against North Korea. The sanctions aim to choke the supply of oil to Pyongyang, and could have an adverse effect during the winter.

Abe added that he wanted to amend Japan’s Constitution, which effectively bans the country from holding active armed forces. “I would like this to be a year in which public debate over a constitutional revision will be deepened further,” he said.

Abe was re-elected the prime minister of Japan on November 1 after his ruling coalition won a two-thirds majority in the snap elections held in October. Abe’s Liberal Democratic Party may present its ideas for constitutional amendment during the next session of the National Diet – the Japanese legislature – from January 22, The Japan Times reported.