British Prime Minister Theresa May, German Chancellor Angela Merkel and recently, Ukrainian President Petro Poroshenko: They're among the many world leaders who have shaken hands with US President Donald Trump. Some of these handshakes have been perfunctory and short, others warm and, at times, unbelievably long. But one key handshake has yet to happen, and that's the one between Trump and Russian President Vladimir Putin. The first opportunity is just around the corner, at the G20 summit in Hamburg. After much speculation, Moscow's foreign ministry has now confirmed that the two are scheduled to meet on Friday, the first day of the summit.

Putin's patience with Trump

Expectations for a top-level meeting between the US and Russia have seldom been so high. Moscow would have liked to see Putin and Trump shake hands much sooner. "It's about normalizing the dialogue," said Russian Foreign Minister Sergey Lavrov. Russia is hoping for a new start in bilateral relations, which have been lurching from one low point to the next ever since the annexation of Crimea. And Trump has been feeding Moscow's hopes by repeatedly praising Putin's qualities as a strong leader and promising better ties with Russia.

But that turnaround has yet to materialize. At home, Trump has been under pressure for months over allegations that Russia interfered in the US election to his benefit, and that his campaign colluded with the Russian government. Both Trump as well as Russian officials deny the accusations. The new US administration has left in place sanctions imposed on Moscow under former president Barack Obama; recently it even introduced new sanctions.

Moscow has shown understanding for Trump, putting his reluctance to turn the page down to the domestic political situation in the US and pressure from his opponents.

"We are patient," Putin has repeatedly said with regard to Washington. Russia has avoided any criticism of Trump, and the new sanctions imposed by his government. And when Trump referred to the "Russian threat" during a NATO speech in Brussels in May, Putin took it in stride, dismissing it as "nothing special" in an interview.

Muted expectations

But behind the scenes, there must have been a sense of disillusionment, says Russian foreign policy expert Lilija Shevtsova. She describes the end of February as the tipping point for the mood in Moscow's political circle.

"Putin was standing with an outstretched hand, waiting for Trump to take the initiative," said Shevtsova, who currently works as an associate fellow at the UK-based policy institute, Chatham House. "But then he had to make the realization that Trump is an unpredictable politician who's just as likely to be tough on Moscow."

With his cruise missile strike in Syria, Trump has already shown that he's willing to depart from the cautious course taken by the Obama government, Shevtsova said. And he's also prepared to compete with Russia, for example when it comes to worldwide deliveries of liquefied gas, she added.

"It is a first meeting on the sidelines of a summit - it's not a bilateral meeting," said Ivan Timofeyev of the Russian Council on Foreign Policy, a government-founded network of experts. Direct talks between Putin and Trump are "long overdue."

"The most important thing is for them to get to know one another personally," Timofeyev said, adding that a breakthrough is not expected in Hamburg.

Shevtsova agrees that a handshake and agreement on a future face-to-face would be a success: "Their meeting will be judged on the ability of both leaders to create a mechanism to overcome their mutual distrust."

Terrorism, Syria, Ukraine

Moscow's priorities at the meeting in Hamburg point to a desire to find common ground and avoid conflict. A spokesperson from the Russian foreign ministry has said that Putin will focus on the fight against terrorism when speaking with Trump. "There can be no victory in the war on terror without cooperation between Russia and the United States," the ministry said.  

There is likely to be a focus on the common effort in the fight against the so-called "Islamic State" (IS) terrorist militia in Syria and Iraq. Recently, tensions escalated after the Western alliance under US leadership shot down a Syrian fighter jet. In protest, Russia, which has been giving military support to Syrian President Bashar al-Assad, stepped away from an agreement with the US to exchange information on air force movements. Reinstating this agreement would be an important step for Putin and Trump to take when they meet in Hamburg, said Shevtsova.

In her view, Russia has already given the US a "gift" with the so-called de-escalation zones for Syria. "But America didn't see that as a gift, and is not yet prepared to support it," she said.

It's also likely that Putin will want to address the issue of nuclear weapons in Hamburg - a topic that interests both Russia and the US because of the current threat posed by North Korea. However the experts do not expect any movement on the issue of Ukraine. There appears to be no solution in sight to the conflict, for which Kyiv and the West blame Moscow.