Following a surprising order to start nuclear weapons testing that raised the possibility of heightened tensions between superpowers, US President Donald Trump returned to Washington on Thursday.
Trump, who regularly brags about being a peace president, made the social media revelation shortly before he met with Chinese leader Xi Jinping in South Korea for a summit.
However, there were many questions raised by Trump's declaration, mostly regarding whether he intended to test weapons systems or actually carry out test explosions, which the US hasn't done since 1992.
Iran, a major American adversary, denounced the command as "irresponsible."

Vice President JD Vance stated that testing were necessary to make sure the US nuclear arsenal "functions properly," but he did not specify the kind of tests that Trump had requested.
"The statement from the president "speaks for itself," Vance told reporters at the White House yesterday.
"It's an important part of American national security to make sure that this nuclear arsenal we have actually functions properly, and that's part of a testing regime," he said.
Nevertheless, Trump's remarks amounted to extraordinary nuclear sabre rattling.
It happened a few days after Russia said that it had tested nuclear-powered cruise missiles and naval drones with nuclear capability.
"Because of other countries testing programs, I have instructed the Department of War to start testing our Nuclear Weapons an equal basis," Trump stated on Truth Social.

In his first term as president, Trump also asserted that the United States possesses more nuclear weapons than any other nation.
But it didn't seem to be the case.
In its most recent annual report, the Stockholm International Peace Research Institute (SIPRI) reports that Russia has 5,489 nuclear weapons, while the United States has 5,177 and China has 600.
Minutes before his Xi summit, Trump stated in his post that China should "be even within 5 years."

A bully with nuclear weapons
The Kremlin questioned Trump's knowledge of Russia's military operations.
According to Dmitry Peskov, the recent weapons exercises "cannot in any way be interpreted as a nuclear test," he told reporters.
"We hope that the information was conveyed correctly to President Trump."
Then, Peskov hinted that if Trump did it first, Russia would test its own live warheads.
Guo Jiakun, the spokesperson for China's foreign ministry, encouraged the US to "earnestly abide" by a worldwide prohibition on nuclear testing.
Although Russia and the US regularly conduct military exercises involving nuclear-capable weaponry, both nations maintain a de facto ban on nuclear warhead testing.

Iran's foreign minister described the Trump order to resume testing as "regressive and irresponsible," and he said it posed a threat to global security.
"A bully with a nuclear weapon is starting to test atomic weapons again. Iran's peaceful nuclear program has been maligned by the same bully," Abbas Araghchi wrote on social media.
According to his deputy spokesperson, Antonio Guterres, the head of the United Nations, stated that "nuclear testing can never be permitted under any circumstances."
All atomic test explosions, whether for military or civilian uses, are prohibited under the Comprehensive Nuclear-Test-Ban Treaty, to which the US has been a party since 1996.
Trump told reporters on Air Force One that it was "appropriate" to resume nuclear testing even though it had been "many years" since the US had done so.

In his comments to reporters, Trump further muddied the issue by restating his earlier assertion that he wants talks with China and Russia on decreasing nuclear weapons forces.
"Denuclearisation would be a tremendous thing," stated he
1992 was the last US test.
In addition to two nuclear attacks on Japan during World War II, the United States carried out 1,054 nuclear tests between July 16, 1945, when the first test was carried out in New Mexico, and 1992.
It is the only nation to have engaged in warfare using nuclear weapons.
In September 1992, a 20-kiloton subterranean explosion at the Nevada Nuclear Security Site marked the last nuclear test explosion in the United States.

In October 1992, then-President George H.W. Bush placed a ban on additional testing, which has been upheld by succeeding administrations.
Non-nuclear and subcritical tests utilising sophisticated computer simulations took the place of nuclear testing.