While the first official bilateral meeting between president Donald Trump and Russian president Vladimir Putin is still some three hours away, moments ago the two presidents finally met unofficially as the Group of 20 leaders met in Hamburg, at which point Trump and Putin shook hands.

Donald Trump and Vladimir Putin shake hands for the first time pic.twitter.com/xJ5tgcmCKS — The Telegraph (@Telegraph) July 7, 2017

The highly anticipated first handshake happened in private earlier today much to the disappointment of the world's press who were poised to capture the "historic" moment.

The handshake's happened! At the G20 Kremlin spokesman says Trump & Putin "shook hands & said they'll see each other soon" for the bilateral — Steve Rosenberg (@BBCSteveR) July 7, 2017

But fear not: the two leaders will meet again later this afternoon for a low-key meeting on the summit sidelines.

As is widely known, the meeting between Putin and Trump is the most highly anticipated face-to-face showdown of the summit. They are later expected to have a meeting lasting one hour. As the Telegraph notes, it will be a sit-down overshadowed by the investigations into whether Mr Trump's campaign coordinated with Moscow during last year's presidential election.

The leaders are expected to discuss a series of troubling foreign policy issues, including the conflict in Syria and Russia's provocations in Ukraine. But much of the focus – both in Washington and Moscow – will be on whether Trump broaches the the US media's favorite topic: whether Russia meddled in the US election, although as Putin has repeatedly stated on the record, this never happened.

Before the meeting on Friday, Trump tweeted that he was looking forward to the visit, saying there was "much to discuss."

I look forward to all meetings today with world leaders, including my meeting with Vladimir Putin. Much to discuss.#G20Summit #USA???????? — Donald J. Trump (@realDonaldTrump) July 7, 2017

Putting the press on edge, Trump also tweeted early Friday morning that “everyone here is talking about” how Democrats handled the hacking related to last year’s presidential election, saying "everyone here is talking about why John Podesta refused to give the DNC server to the FBI and the CIA. Disgraceful!"

Everyone here is talking about why John Podesta refused to give the DNC server to the FBI and the CIA. Disgraceful! — Donald J. Trump (@realDonaldTrump) July 7, 2017

Trump may have been referring to the recent report that the DNC server - the most critical evidence as to who really hacked the Democrats - continues to be withheld from Special prosecutor Mueller.

The DNC initially refused to allow the FBI direct access to its servers in the wake of the cyberattack. Former FBI Director James Comey told Congress in January that the agency and the DNC ultimately agreed that a “highly respected private company” would examine the servers and share its findings with the FBI. The House Intelligence Committee interviewed Podesta, whose personal account was breached, in its ongoing probe of the Russian hacks late last month.

Further angering the "deep state" which is eager to see relations between the US and Russia falter, during a news conference in Poland yesterday, Trump refused to accept the conclusion by multiple US intelligence agencies that Russia interfered to try to help Trump win last November. Trump said it could have been Russia, but that other countries could have meddled, too. Trump has said he wants to find ways to work with Putin, a goal made more difficult by sharp differences over Russia's actions in Syria and Ukraine, and allegations Moscow meddled in the 2016 US presidential election.

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As for the the upcoming historic meeting, "every facial expression and physical gesture will be analysed to read how well Trump, a real estate magnate and former reality television star, gets along with Putin, a former KGB agent" according to the Telegraph. The fear for the US is that the Republican president, a political novice whose team is still developing its Russia policy, will be less prepared than Mr Putin, who has dealt with the past two US presidents and scores of other world leaders.

Trump has long expressed a desire for warmer relations with Russia, and has proposed increased cooperation in the fight against extremist groups such as ISIS.

It's unclear what the two leaders will discuss in their bilateral meeting on Friday, though the issue of the ongoing civil war in Syria is likely to be a key issue. The U.S. and Russia back opposing sides in the fight.

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PS. For those wondering, here is the handshake between Putin and Theresa May, which took place as the Russian president was talking to Abe and Tusk: