Donald Trump's body language was "completely different" at his meeting with Vladimir Putin, than it was with other world leaders, according to body language experts who have analysed his meetings with other world leaders.

The US President's awkwardly long handshakes have become infamous since he took office, with his habit of aggressively yanking other heads of state towards him. Psychologists say this is a tactical move to assert dominance.

Mr Trump's first meeting with the Russian President at the G20 summit attracted intense scrutiny against a backdrop of allegations that Moscow meddled with the US election.

Footage showed the pair sharing a warm handshake but the US President gave his Russian counterpart a friendly pat on the arm as they first greeted each other among mingling leaders at the G20 summit in the German city of Hamburg.

Unlike in previous meetings with premiers, Mr Trump did not lean in and there was no sign of his trademark aggression.

The pair briefly shook hands for a second time at a media photo call, when the US President leaned back in his seat and refrained from pulling Mr Putin towards him.

Tonya Reiman, author of the book The Power of Body Language, described Mr Trump's manner as "completely different" from his encounters with other leaders.

“Every single [previous] handshake I’ve watched - and I’ve watched them all - he’s the one who wants to be the dominant force [and] literally makes you lose your footing," she told the Boston Globe.

“You see Trump is very guarded," added Lillian Glass, an American communication and body language expert. "He doesn’t put all smiles out, and he doesn’t lean in to Putin, he leans away."

Donald Trump and Vladimir Putin meet at G20 summit

She suggested Mr Trump was wary of appearing "chummy" with the Russian President, amid ongoing investigations into claims Moscow interfered in the US Presidential election to his benefit.

"From what was swirling around, he doesn’t want to give Americans the wrong impression and he doesn’t want to give the world the wrong impression,” she added.

Other experts noted deference in Mr Trump's stance towards his Russian counterpart in their first encounter.

"Putin is standing up straight [in] his body position and Trump is the one that walks toward him,” said Patti Wood, author of Snap: Making the Most of First Impressions, Body Language, and Charisma.

“Trump is the one who initiates the handshake and Trump is leaning his whole body - not quite in bow, but leaning forward as a bid to bow.”

The two presidents spent two hours and 16 minutes in a one-to-one meeting on Friday discussing issues including the Syria conflict, Ukraine and terrorism.

The Trump administration claimed the US President also pressed Mr Putin over Russia’s alleged interference in the US election during a “very robust and lengthy exchange”.