“Why would Kim Jong-un insult me by calling me ‘old,’ when I would NEVER call him ‘short and fat?’” Trump said in a tweet from Hanoi.

“Oh well, I try so hard to be his friend -- and maybe someday that will happen!”

His remarks came upon the wrap-up of the Asia Pacific Economic Cooperation summit in Vietnam. The summit marks the near-end of US President Donald Trump’s 12-day Asia tour, which Trump has so far used as a platform to address and denounce Pyongyang’s decadeslong nuclear drive and its threats to regional security.

On Saturday, North Korea criticized Trump’s Asia trip saying that “reckless remarks by an old lunatic like Trump will never scare us or stop our advance,” in an official statement issued by its Foreign Ministry. It also labeled the trip a “warmonger’s trip for confrontation.”

However, the latest exchange between the two struck a more moderate tone compared to their recent “war of words” after the North’s sixth and largest nuclear test on Sept. 3. Trump had threatened to “totally destroy” North Korea on its ongoing provocations toward the US and its allies.

North Korea also took a low-key stance on the matter, unlike Kim’s previous decision to release a rare direct statement refuting Trump’s UN General Assembly speech in September.

Pyongyang has been taking its longest hiatus in military provocations in recent months, despite its warnings of detonating a hydrogen bomb over the Pacific.

Although both sides displayed a shift in tone from aggressive rhetoric, the idea of a dialogue channel between the two is uncertain as Trump has stressed denuclearization as a precondition for talks.

US Secretary of State Rex Tillerson said last month that the US is maintaining direct channels of communication with North Korea, but Trump dismissed the idea as a “waste of time.”

“There is a brighter path that North Korea can walk if it begins walking down the path toward denuclearization,” said a senior White House official aboard Air Force One heading to China after wrapping up his 24-hour stint in South Korea.

Trump also voiced optimism on cooperation with China to bolster its policy of “extended deterrence” against North Korea, in a separate tweet.

“President Xi of China has stated that he is upping the sanctions against (North Korea), said he wants them to denuclearize,” Trump said, referring to a talk with his Chinese counterpart Xi Jinping on the sidelines of the summit.

“Progress is being made,” he added.

Xi had previously pledged to strictly implement the latest United Nations Security Council resolutions against North Korea, in a joint statement with Trump, during the US president’s state visit to Beijing last week. Trump has been repeatedly asking Beijing to use its economic clout against the North, as it accounts for 90 percent of the reclusive nation’s foreign trade. He has also expressed frustration over China’s lukewarm and vague response toward the request.

China is expected to pile on its September ban of shutting down North Korean-owned businesses there by early January, on top of cutting off gas and limiting shipments of refined petroleum products. Crude oil, which represents a large portion of China’s energy supply to the North, was not subjected to the ban.

In the joint statement, Trump strongly urged the international community to join in the movement to further isolate North Korea to bring about its denuclearization.

“We agreed not to replicate failed approaches of the past, and there were many,” said Trump. “All responsible nations must join together to stop arming and financing and even trading with the murderous North Korean regime.”

The US president also said that increased cooperation between Washington and Beijing wields the power to “finally liberate this region and the world from this very serious nuclear menace.”

But senior government officials and experts in South Korea and the US are taking note of the North’s fast-developing weapons program, which many believe is “nearly complete.”

On Sunday, Japan’s Asahi Shinbun reported that Pyongyang has conducted a series of combustion experiments for a new solid-fueled missile engine, citing military sources. The tests may have been for an upgraded version of a ground-to-ground medium-to-long range Pukguksong-2 ballistic missile or a new submarine-launched ballistic missile, it said.

It also added the next military provocation may come around Dec. 1, when the North Korean military kicks off its winter training exercise.

Meanwhile, South Korea and the US launched four-day joint naval exercises on Saturday in waters near the Korean Peninsula in a show of force against North Korea, South Korea’s Joint Chiefs of Staff said. North Korea has actively lambasted the drills as dress rehearsals for an invasion despite the allies’ reiteration that the exercises are defensive in nature.

By Jung Min-kyung (mkjung@heraldcorp.com)