Japanese Prime Minister Shinzo Abe got a hug at the front door of the White House on Friday.

“I shook hands, but I grabbed him and hugged him because that’s the way we feel,” President Donald Trump told reporters during a joint news conference with Abe a bit later.

Left unexplained was Trump’s 19-second handshake with the visiting Japanese leader while they both sat for the cameras in the Oval Office.

Prolonged handshakes between leaders are not unusual for such staged media encounters, known in the business as a “camera spray,” but they are most always analyzed for the state of relations between the two sides.

Friday’s complex clasp immediately set social media abuzz. Commenters on Twitter variously described it as “awkward,” “never-ending” and “weirdly aggressive.”

Trump said something about “strong hands.” (It wasn’t clear whether the president was complimenting Abe’s grip or talking about his own famous fingers.)  

At the end of the encounter, which included a double-handed Trump yank and grab, the normally subdued Abe stood mouth agape with a wide-eyed expression, and planted his hands into the armrests of his chair as he looked away from the president.

WATCH: Trump and Abe Shake Hands in Oval Office

Expert astonished   

A specialist in interpersonal communication exclaimed “Oh, my God!” three times when first reviewing the clip of Friday’s Oval Office encounter.

Human behavior researcher Patti Wood said that by initially offering his hand palm up to his visitor, Trump “wants to show he’s subordinate” — a highly unusual gesture for the veteran dealmaker.  

But then Trump put Abe “off kilter,” Wood told VOA, by dragging Abe’s hand closer to him. This is a presidential gesture seen previously, such as in greeting Vice President Mike Pence or Supreme Court nominee Neil Gorsuch.  

Abe’s discomfort, according to Wood, can be seen from his free hand: fingers curled, close to his body.

“Trump likes to break expectations,” added Wood, an author who has been an instructor on body language and communications at several universities.

Trump then proceeds to pat Abe’s hand, she noted, to show “I’m still in power. I’m going to show dominance.”

Another veteran interpreter of the language of the body, former University of South California professor Lilian Glass, saw the encounter in a different light.

“Trump is a very affectionate guy, and people don’t realize it,” she told VOA.

According to Glass, a grinning Trump’s gestures with Abe meant “We’re with you” and “I really like you.”

During their time before the cameras, the two leaders were having fun, she added.

Cultural disconnect

Glass, who helps train politicians and Hollywood actors how to communicate, explained that if there is any disconnect between Trump and Abe, it is a cultural one, as Japanese handshakes tend to be “very, very limp.” So the prime minister encountering the presidential hand-clamp was “not used to that behavior, but it’s the American way.”

Abe, she suggested, would most likely have been comfortable with a diplomatic bow, but if Trump “had to bow, it would be weird.”

Trump’s predecessor, Barack Obama, faced criticism in 2009 when he combined a handshake and 45-degree bow facing Japanese Emperor Akihito. At the time, historians noted that a Republican president, Richard Nixon, had bowed deeply, without a resulting uproar, in a 1971 encounter with Akihito’s father, Emperor Hirohito.

Before he entered politics, Trump wasn’t much for shaking hands, let alone bowing. A self-declared “germaphobe,” Trump initially eschewed offering his hand to potential voters on the hustings. He eventually embraced the practice, however, and made it part of the unconventional campaign that led him to the Oval Office and encounters such as the one he enjoyed with the Japanese leader on Friday.