President Barack Obama has said that Republican Donald Trump proves he is not qualified to be president "every time he speaks", adding that he was confident Americans would ultimately reject the brash billionaire on election day.
Mr Obama, closing out his final presidential trip to Asia, said his meetings with foreign leaders during the trip had illustrated that governing is "serious business" requiring knowledge, preparation and thought-out policies that can actually be implemented. He urged Americans not to allow the "outrageous behaviour" seen amid the campaign-season din to become the new normal.
"The most important thing for the public and the press is to just listen to what he says and follow up and ask questions to what appear to be either contradictory or uninformed or outright wacky ideas," Mr Obama said.
Throughout the campaign, Mr Obama has repeatedly denounced Mr Trump and deemed him "unfit" to serve as commander in chief, arguing that he's pulling the Republican Party in a dangerous and unprecedented direction.
Mr Obama has endorsed Hillary Clinton and has said he plans to campaign full-force for the Democrat ahead of the November election.
Mr Obama's remarks came at the end of a gruelling nine-day trip that took him to Laos and China following US stops in Nevada, Hawaii and Midway Atoll in the Pacific Ocean. It is the last of 10 trips Mr Obama paid as president to Asia, where Mr Obama lived as a youngster with his mother in Indonesia.
"When I think back to the time I spent here as a boy, I can't help but be struck by the extraordinary progress that's been made by the region in the decades since, even if there's still a lot of work to be done," Mr Obama said.
At the top of the list of unfinished business is the Trans-Pacific Partnership, a 12-nation free trade deal Mr Obama helped broker. That deal awaits ratification in the US Congress, where there is opposition from both parties. But Mr Obama said he planned to do everything possible to persuade politicians to approve it this year.
With his presidency nearing an end, Mr Obama's agenda has narrowed to a few key goals he hopes to complete before his successor takes over. Asked to acknowledge he would not be able to fulfil his campaign promise to close the Guantanamo Bay detention centre, Mr Obama pushed back.
"I am not ready to concede," Mr Obama said, adding that his administration was making progress in reducing the prison's population.
He bristled at the suggestion he had been slighted in Asia or that leaders in the region were rejecting his leadership - a criticism levelled by Mr Trump, who said he would have picked up and left had he been treated the way Mr Obama was in Asia.
The start of the trip was overshadowed by tense moments on the tarmac when Chinese officials clashed with White House aides and appeared to have failed to secure a staircase for Mr Obama's plane - moments that exploded on social media.
The awkwardness continued days later when Philippine President Rodrigo Duterte called Mr Obama a "son of a bitch" and warned him not to challenge him in their planned meeting in Laos, leading Mr Obama to call it off.
The two did end up shaking hands during a brief interaction on the summit's sidelines. Mr Obama said he had told Mr Duterte that their aides should confer on how to move forward, adding that the spat would have no effect on the close cooperation between the longtime treaty allies.
"I don't take these comments personally, because it seems as if this is a phrase he's used repeatedly, directed at the Pope and others," Mr Obama said of the slur. "I think it seems to be just a, you know, a habit, a way of speaking for him."
As an example of progress on his trip, Mr Obama pointed to discussions with Southeast Asian leaders about disputes over China's territorial ambitions in the South China Sea. In a concluding joint statement, the leaders were expected to issue a mild rebuke to China without referencing it by name or mentioning a recent international arbitration ruling against Beijing.
"I realiSe this raises tensions," Mr Obama said earlier on Thursday about the ruling. "But I also look forward to discussing how we can constructively move forward together to lower tensions and promote diplomacy and regional stability."
On his last day in Asia, Mr Obama met with Indian Prime Minister Narendra Modi, whose help Mr Obama is seeking to galvanise further action on climate change, especially among developing countries.
The White House said Mr Obama had affirmed his support for India's participation in the Nuclear Suppliers Group, a consortium aimed at preventing civilian nuclear technology from diverted for military use. Pakistan, India's longtime adversary, opposes India's membership in the group.