MANILA, Philippines — Hours after President Donald Trump taunted North Korean leader Kim Jong Un on Twitter, suggesting he is "short and fat," the White House chief of staff insisted he doesn't carefully follow Trump's comments on social media and tells other aides not to react to them.

"Someone, I read the other day, said we all just react to the tweets," said Chief of Staff John F. Kelly, speaking with a group of reporters after a presidential news conference Sunday in Vietnam. "We don't. I don't. I don't allow the staff to. We know what we're doing.

"Believe it or not, I do not follow the tweets," Kelly said.

"I find out about them," he continued. "But for our purposes, my purpose, is we make sure the president is briefed up on what he's about to do."

Kelly's comments came as Trump prepared for another controversial moment in his five-nation Asia tour — a scheduled meeting with Rodrigo Duterte, the Philippine president, who has a history of human rights abuses. Trump had an initial encounter with Duterte in Manila on Sunday, exchanging handshakes and toasts with him at a gala dinner opening an international conference.

By Monday morning, the 11th day of Trump's grueling Asia tour, the U.S. president looked increasingly tired, crossing his arms and struggling to keep his eyes open during a multinational dance tribute that served as part of the welcome ceremony for the Association of Southeast Asian Nations summit.

Minutes before the dance ceremony, he grew confused when the assembled leaders of the member countries were asked to perform a cross-body handshake. He laughed and then grimaced, exaggeratedly, as he reached cross-wise to connect with Duterte and Tran Dai Quang, the president of Vietnam.

Trump's physical stamina on the lengthy trip and his Twitter habits, and how to treat them, have been concerns for the White House staff on the Asia trip. To handle the former, aides have tried to pace the president, building downtime into the schedule. To handle the latter, Kelly suggested, he tries not to focus too heavily on them.

"The tweets don't run my life — good staff work runs it," he said.

Trump has been less active than usual for him on Twitter during his 12-day trip. But that changed in Vietnam with a short burst of tweets that hit the internet Saturday night in the U.S., commenting on Russia, "all the haters and fools," the "Fake News Media" and "Crooked Hillary Clinton."

His third tweet of the series was of the type that had the potential to ramp up tensions with a dangerous nuclear foe, North Korea. Rallying Asian nations to the cause of ending North Korea's nuclear program is the central focus of Trump's trip.

He has exchanged personal insults for months with Kim, a leader about whom U.S. intelligence agencies know relatively little. The Kim government recently called Trump a "lunatic old man," according to state media.

Trump retaliated in kind: "Why would Kim Jong-un insult me by calling me 'old,' when I would NEVER call him 'short and fat?' " he tweeted. "Oh well, I try so hard to be his friend — and maybe someday that will happen!"

Referring to Trump's tweets, Kelly said, "They are what they are." And, in response to a question about whether he needs to take them into account to develop policy, Kelly insisted he does not.

"We develop policy in the normal traditional staff way," he said.

Asked about the meeting with Duterte, Kelly said human rights would be a "hot topic" in the Philippines but declined to make definitive statements about Duterte's possible role in abuses — or whether reports of abuses were true.

"I mean there's an awful lot of reported extrajudicial heavy-handedness," Kelly said.

Reporters asked Kelly whether he believed those reports. "Well, we'll have to see," Kelly replied.

A reporter pressed him again: "You're not sure?"

"I'm not sure," Kelly responded.

Philippine police, at Duterte's direction, have killed thousands of people accused of drug crimes without trials, incurring condemnations from human rights groups, the United Nations, Congress and the European Union. The White House has said Trump shares a "warm rapport" with Duterte.

Kelly downplayed the meeting, saying the president's primary purpose for traveling to the Philippines is to attend two conferences that will attract leaders from around the world.

"I would say the conference is the most important thing in the Philippines," Kelly said. "And, obviously, since the president's there, he'll meet with (Duterte) but nothing formal."

Trump, who also has spoken warmly of Russian leader Vladimir Putin and China's Xi Jinping, was asked by reporters aboard Air Force One on Saturday about having close relationships with strongmen.

"I'll be honest with you, I think I have a great relationship with every single one — every person in that room today," Trump said, referring to leaders from around the world who joined him at the Asia-Pacific Economic Cooperation summit in Vietnam, including leaders from many democratic nations.

But even as Trump and Duterte have exchanged some kind words, the traditional U.S. ally is also courting China. Two hours before his dinner with Trump on Sunday, Duterte cast further doubt on American economic leadership by describing China, which has the world's second biggest total economic output, as the global economic leader.

"Today China is the No. 1 economic power, and we have to be friends," Duterte said, speaking at a business forum held at a Manila casino.