Linda Thomas-Greenfield, U.S. ambassador to the United Nations / AP-Yonhap

The United States will push for additional U.N. sanctions on North Korea should the recalcitrant state go ahead with its feared nuclear test, U.S. Ambassador to the U.N. Linda Thomas-Greenfield said Tuesday.

The remarks come after the U.N. Security Council (UNSC) failed to pass a U.S.-proposed sanctions resolution on North Korea last week due to opposition from China and Russia.

"First of all, we need to enforce the sanctions that we have already authority to enforce," the U.S. diplomat told reporters in New York, according to AFP.

"And we certainly, as we attempted in this last resolution, will push for additional sanctions," she added when asked if the U.S. would push for a new sanctions resolution if Pyongyang goes ahead with a nuclear weapon test.

U.S. National Security Advisor Jake Sullivan had repeatedly warned that a North Korean nuclear test may be in the offing, possibly during President Joe Biden's recently concluded trip to South Korea and Japan.

Pyongyang fired three ballistic missiles on the heels of Biden's first visit to Asia last week, marking its 17th show of force this year.

Officials in Seoul and Washington have noted that Pyongyang may have already completed "all preparations" for a nuclear weapon test. The country conducted its last and sixth such test in September 2017.

Shortly after the U.S.-proposed sanctions resolution was vetoed Friday by China and Russia, both permanent members of the UNSC and close allies of North Korea, Thomas-Greenfield said the U.S. will continue to hold the North accountable for the threat it poses to the region and the rest of the world.

"I am beyond disappointed that the Council has not been able to unify in opposition (to) the DPRK's unlawful WMD and ballistic missile programs. And that failure rests on China and Russia alone," she has said in a released statement, referring to North Korea by its official name, the Democratic People's Republic of Korea.

"The United States will not stand down as long as Kim Jung-un continues his unlawful WMD and ballistic missile program and seeks to threaten regional and global security with more destabilizing ballistic missile launches," she added. (Yonhap)