A clear policy difference emerged between Japan and the United States when they had bilateral consultations before a U.N. panel adopted a Japanese resolution this month calling for the total elimination of nuclear weapons, according to diplomatic sources.

The United States had opposed including some sentences referring to the importance of Article 6 of the Nuclear Non-Proliferation Treaty and agreements reached at the review conferences on the NPT in 1995, 2000 and 2010 in the Japan-sponsored U.N. resolution, the sources who spoke on condition of anonymity recently told Kyodo News.

The article, which was not mentioned in a similar U.N. resolution the previous year, calls on nuclear-armed states to pursue nuclear disarmament.

The resolution, titled “United action with renewed determination toward the total elimination of nuclear weapons,” was adopted by the First Committee on disarmament issues at the U.N. General Assembly on Nov. 1.

But Japan’s key ally the United States abstained, calling it a “step back” from last year’s document, which it supported.

According to the sources, before the resolution was adopted by the committee, U.S. diplomats raised strong concerns about the draft that mentioned the article.

Also, the U.S. diplomats expressed strong opposition to a paragraph in it that urged all countries to take steps agreed to in the final documents of the NPT conferences, according to the sources.

The United States characterized the past agreements as “out of date” under the current security environment, the sources said.

The final document agreed to in 2000, for example, said there should be an “unequivocal undertaking” by nuclear weapon states to accomplish the complete elimination of their nuclear arsenals.

The U.S. diplomats’ oppositions reflected the administration of President Donald Trump’s reluctance to embrace the obligation of nuclear disarmament under the NPT.

The Trump administration also announced last month a decision to withdraw from the 1987 Intermediate Nuclear Forces Treaty, which helped end the Cold War.

The United States also asked Japanese diplomats to delete a sentence urging North Korea to “sign and ratify the Comprehensive Nuclear-Test-Ban Treaty” from the draft resolution, because the Trump administration has already decided not to pursue ratification of the treaty itself, according to the sources.

The Japanese government deliberated the U.S. requests before concluding that it should reject them because Japan is the only country to have suffered the devastation of atomic bombings and cannot compromise on its fundamental principles to advocate nuclear disarmament.

“It is a red line for us,” a Japanese source said.

However, the exposed policy difference indicates there may be difficulties between Japan and the United States in cooperating on nuclear disarmament agendas, as the NPT regime will mark the 50th anniversary in 2020 of the treaty’s entry into force.

The U.N. resolution, penned by Tokyo, again omitted any reference to the Treaty on the Prohibition of Nuclear Weapons in view of its reliance on the U.S. nuclear umbrella.

Taking these realities into consideration, for the past few years the administration of Prime Minister Shinzo Abe has said both at home and abroad that it will seek to play a constructive role as a “bridge-builder.”

But the ambivalent nature of Japan’s anti-nuclear policy has drawn criticism from nuclear disarmament advocates.

“Being a bridge-builder does not mean that Japan just takes the middle ground between nuclear weapon states and non-nuclear weapon states,” Tatsujiro Suzuki, a Nagasaki University professor, said. “As a victim nation of nuclear bombs, Japan should keep a clear distance from the U.S. nuclear arming policy.”

“A notion of ‘humanitarian consequence,’ as emphasized in the nuclear ban treaty, is the element Japan has advocated for a long time,” said Suzuki, who is also director of the Research Center for Nuclear Weapons Abolition at the university. “Even though Japan is not able to sign it right now, it should declare it will pursue future admission to the treaty. After that, Japan could be trusted as a bridge-builder.”

Tokyo has drafted and put forward a similar motion calling for the abolition of nuclear arms for the past 25 years, with the latest version endorsed by 160 countries, up 16 from last year.

Four countries — China, North Korea, Russia and Syria — voted against it and 24, including the United States, abstained.