US discussed holding first nuclear test in decades: Report

President Donald Trump's administration has discussed holding the first US nuclear test since 1992 as a potential warning to Russia and China, the Washington Post reported Friday.

Such a test would be a significant departure from US defense policy and dramatically up the ante for other nuclear-armed nations. One analyst told the newspaper that if it were to go ahead it would be seen as the "starting gun to an unprecedented nuclear arms race".

The report, citing one senior administration official and two former officials, all who spoke anonymously, said the discussion had taken place at a meeting on May 15.

It came after some US officials reportedly claimed that Russia and China were conducting their own low-yield tests. Moscow and Beijing have denied the claims, and the US has not offered evidence for them.

The senior administration official said that demonstrating Washington's ability to "rapid test" would be a useful negotiating tactic as the US seeks a trilateral agreement with Russia and China over nuclear weapons.

The meeting did not conclude with any agreement, and the sources were divided over whether discussions were still ongoing. Nuclear non-proliferation activists were quick to condemn the idea. "It would be the starting gun to an unprecedented nuclear arms race," Daryl Kimball, executive director of the Arms Control Association, told the Post.

He added that it would also likely "disrupt" negotiations with North Korean leader Kim Jong-Un, "who may no longer feel compelled to honour his moratorium on nuclear testing." Beatrice Fihn of the International Campaign to Abolish Nuclear Weapons (ICAN), the group that won the 2017 Nobel Peace Prize, warned a Trump nuclear test could "plunge us back into a new Cold War".

"It would also blow up any chance of avoiding a dangerous new nuclear arms race. It would complete the erosion of the global arms control framework," she said in a statement.

The Trump administration has repeatedly shaken up US defense policy.

The Washington Post report came one day after Trump announced that he plans to withdraw from the Open Skies treaty with Russia, which was designed to improve military transparency and confidence between the superpowers.

It is the third arms control pact Trump has abrogated since coming to office.

Russia has insisted it will abide by the 18-year-old agreement, which seeks to lower the risk of war by permitting each signatory country's military to conduct a certain number of surveillance flights over another member country each year on short notice.