WASHINGTON -- The United States and Japan reaffirmed their commitment to the complete denuclearization of the Korean Peninsula Thursday, urging North Korea to quickly return to the Non-Proliferation Treaty (NPT).

The countries also urged all UN member countries to fully implement UN Security Council sanctions on North Korea.

"We are strongly committed to the complete, verifiable, and irreversible dismantlement of all of North Korea's nuclear weapons, other weapons of mass destruction and ballistic missiles of all ranges, as well as related programs and facilities, in accordance with relevant UN Security Council resolutions (UNSCRs)," the countries said in a joint statement.

"We urge North Korea to abide by all relevant UNSCRs and return at an early date to and fully comply with the NPT and IAEA safeguards. We call on the entire international community to fully implement these relevant UNSCRs," they added.

The US-Japan joint statement comes after North Korea hinted at the resumption of its nuclear and long-range ballistic missile testing.

Pyongyang said on Thursday (Seoul time) that it will consider resuming "temporarily-suspended activities" that it said were suspended as part of efforts to build trust with the US.

The North has maintained a self-imposed moratorium on nuclear and long-range missile testing since November 2017. However, the country has staged more than 10 rounds of short-range missiles launches since Joe Biden took office a year earlier, including four missile tests since the start of this year.

The UN Security Council was Thursday set to discuss additional sanctions on North Korea proposed by the US for its latest missile tests, but reports said the move has been delayed by China, one of the five veto-power wielding permanent members of the Security Council.

The reports also said the delay can last up to six months and that it can also be extended by another three months, which could permanently remove the US proposal for additional sanctions from the UN Security Council.

The US and Japan reiterated the importance of the international nuclear non-proliferation regime, from which North Korea withdrew in 2003.

"Japan and the United States wholly reaffirm their commitment to the NPT, which has been the cornerstone of nuclear non-proliferation and disarmament for 51 years since coming into force," the countries said, adding the 1945 atomic bombings of Hiroshima and Nagasaki serve as "stark reminders that the 76-year record of non-use of nuclear weapons must be maintained."

The joint statement also comes one day before Biden and Japanese Prime Minister Fumio Kishida will hold a virtual summit, the first of its kind since Kishida took office in October.

North Korea remains unresponsive to US overtures since Biden took office. It has also stayed away from denuclearization talks with the US since late 2019. (Yonhap)