Despite the personal chemistry between Russian and US presidents and their pledges to revive ties, Russia-US relations have hardly advanced in 2017 thanks to the ongoing probe of Russian interference in the US presidential election last year, in combination with other factors.

According to experts, the so-called "Russiagate" probe, believed to be the top issue weighing on Moscow-Washington interactions this year, will continue to overshadow ties in 2018.

Investigations started in June 2016 after accusations piled up against Russia over its "influence campaign" and alleged mail hacking aiming to interfere with the US election.

The campaign team of US President Donald Trump was arraigned on its suspected link with Russia for the final win in the election. Trump's inner sanctum members like his eldest son and son-in-law were also interviewed as part of congressional probes.

It seemed the turning point came after former Federal Bureau of Investigation director Robert Mueller's appointment in May as special counsel to oversee the investigation into Russian election interference and related matters.

In October, Mueller's office charged Trump's former campaign manager Paul Manafort, Manafort's deputy Rick Gates, and campaign adviser George Papadopoulos with lying to the FBI. While Manafort and Gates pleaded innocent, Papadopoulos admitted the charges.

On Dec 1, former US National Security Adviser Michael Flynn pleaded guilty of lying to the FBI regarding improper contacts with Russian officials, becoming the first member of the Trump-led administration to be found guilty in the ongoing probe into alleged collusion between Trump's campaign team and Russia.

"Mueller's investigation has certainly unsettled the White House as he has been able to bring charges against several key players－including Paul Manafort and Michael Flynn," said Dan Mahaffee, senior vice-president and director of policy at the Center for the Study of Congress and the Presidency, a Washington-based think tank.

Political crisis

"The White House has cooperated with the investigation, yet at the same time President Trump and many in the conservative media have sought to delegitimize the investigation. Any action against Mueller would likely trigger a major constitutional and political crisis, so it will be something to continue to watch closely in 2018," Mahaffee said.

The so-called Russian intervention in US politics also led to the two countries' mutual expulsion of diplomats and banning media organizations.

Besides the Russia probe, experts from both countries suggested Russian-US relations will suffer as their interests are irreconcilable.

The disagreements between the two countries are "intractable", said a report published in November gathering views of scholars from the Washington-based think tank Center for Strategic and International Studies and the Russian International Affairs Council.

They also thought Russia and the US are not likely to emerge as close partners, as the two perceive threats in each other's policies and actions.

According to Andrei Suzdaltsev, a Russian expert, Moscow now practically has no "freedom of maneuver" regarding diplomatic interaction with Washington, which offered preconditions that "are certainly unacceptable for Russia, like abandoning Crimea".

"The US is still demonstrating such, I would say, an 'indulgently colonial' approach, which leaves us without a possibility to maneuver," said Suzdaltsev, deputy dean of the Faculty of World Economy and Politics of Russia's Higher School of Economics Research University.

He expressed concern about the fact that almost all communications between the two countries were blocked, except for some "situational contacts". There is also no mutual trust for dialogue to restart, Suzdaltsev said.

US-Russian relations are also believed to be affected by shifting global power dynamics in a broader context.

Besides the four-year-old Ukraine crisis, disagreements over the Syrian crisis and the anti-terrorism war played vital parts in the bitter feud.

Although the Russian intervention in Syria and regional anti-terrorism war saw a gradual drawdown in 2017, Moscow kept two military bases in Syria, the Hmeymim air base and the Tartus naval base, which, according to Russian Defense Ministry, will guarantee Syria's future stability.