The stunning, nearly offhand comments, made during a news conference hours after his summit with North Korean leader Kim Jong Un, contradicted countless previous declarations by US political and military officials over the years that the drills are routine, defensive and absolutely crucial.
Following their summit in Singapore, Trump and Kim pledged to denuclearise the Korean peninsula and work for finding a peaceful resolution to seven decades of hostilities between the two countries.
Foreign Ministry spokesman Bahram Ghasemi said that North Korea should approach the summit with "awareness". Perhaps Trump wasn't the one people expected to be making peace, but Americans think this is the best strategy to take. "I am concerned that the summit between Trump and Kim will prove to be a setback in the global efforts to denuclearize North Korea and also introduce instability in the alliance between Seoul and Washington".
While many North Korea experts and defectors welcome the ease in tensions between the USA and North Korea, they faulted Trump for overtly praising an authoritarian leader and failing to bring up human rights violations within North Korea.
"We in Australia, the Australian government is now assessing what we could offer in terms of expertise to assist in that verification process", Ms Bishop said.
"Now would not be the time to ease global sanctions against North Korea". "Only time will tell if North Korea is serious this time, and in the meantime we must continue to apply maximum economic pressure". "The fact that I am having a meeting is a major loss for the United States, say the haters & losers", he tweeted. Trump said sanctions will remain in place for now, but looks forward to lifting them, and added that he has refrained from imposing new sanctions amid the progress being made with North Korea.
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Trudeau and his fellow G7 leaders will try to persuade Trump to reverse the duties when they meet him during the summit. A senior Government source said: "The PM has always said we should engage with Russian Federation but beware".
"China has not made any losses here", said Deng Yuwen, a political analyst based in Beijing.
North Korea also serves as a valuable buffer state between China and USA forces in South Korea.
But the last three presidents secured commitments from North Korea on denuclearisation that North Korea later reneged on.
"I think China may be concerned about losing their leverage over North Korea and fears that North Korea and the USA may enter into an anti-Chinese alignment", said Charles Armstrong, a historian on Korean affairs at Columbia University in NY.
He praised Trump and Kim for their "courage and determination" not to settle for "that outdated and familiar reality but to take a daring step towards change".
Ms Bishop's opposition counterpart Penny Wong echoed concerns that North Korea might not follow through on its promise.