Despite failing to realise the Kremlin's hopes of spearheading a new era in US-Russia ties, President Donald Trump is still Moscow's preferred candidate in the US election over his rival Joe Biden, analysts say.

Russia had high hopes for Trump when he was elected in 2016, at a time its relations with the West were swiftly deteriorating under the presidency of Barack Obama.

According to US intelligence, Moscow went as far as boosting Trump's campaign, in particular by launching hacking attacks against the Democratic Party.

And on Wednesday, the US director of national intelligence accused Russia and Iran of obtaining US voter information and taking actions to influence public opinion in next month's vote -- accusations the Kremlin dismissed as "completely groundless."

At a summit meeting with President Vladimir Putin in Helsinki in 2018, Trump had raised eyebrows by denying outright Russian election interference, saying, "I don't see any reason why it would be" by Moscow.

But Trump "was not the president to break the impasse in Russian-American relations", said Maria Lipman of the Ponars Eurasia research centre.

Not only did the question of Russian interference always loom over Trump's presidency, the two countries also accumulated disagreements on several global issues.

Washington has stepped up its military deployment in Syria after tensions with Russia, which is the main backer of the regime of President Bashar al-Assad.

The United States also withdrew from two major international accords -- the Iran nuclear deal and the Open Skies treaty -- and pulled out from a centrepiece arms control agreement with Russia, the Intermediate-Range Nuclear Forces (INF) treaty.

Moreover, Washington imposed sanctions on companies involved in the construction of the Nord Stream 2 gas pipeline, a joint venture between Russia and Germany, and stepped up sanctions targeting allies of Moscow, including Venezuela and the ex-Soviet republic of Belarus.

The 2018 poisoning of former intelligence officer Sergei Skripal in Britain led to the biggest mutual expulsion of Russian and US diplomats since the Cold War.

At the Helsinki summit, Putin famously admitted that he had "wanted" Trump to win the 2016 election.

But in an interview with Russian TV in early October, Putin complained that since the start of the Trump administration, Russia has been targeted by sanctions 46 times.

This includes the imposing of new sanctions or the expansion of already existing measures.

"You have to look at things objectively," he said, "the intentions President Trump spoke of earlier have not come true".

At a meeting with Putin in Helsinki in 2018, Trump had raised eyebrows by denying outright Russian interference
At a meeting with Putin in Helsinki in 2018, Trump had raised eyebrows by denying outright Russian interference AFP / Brendan Smialowski

But analysts warn Moscow could face an even tougher ride under a Biden presidency.

"After the usual rhetoric of the Democrats, which everybody heard in the past four years, it would be logical if they demanded tougher sanctions," said Alexander Baunov of the Carnegie Centre in Moscow.

In a sign however that Moscow could be preparing for a possible Biden victory, Putin unexpectedly paid tribute to the Democratic Party, which he said shared the same left-wing values that he had grown up with as member of the Communist Party in the USSR.

He even praised "candidate Biden", because he was in favour of extending a landmark nuclear treaty.

Analyst Alexander Shumilin of the Russian Academy of Sciences described the comments as opportunistic.

"He saw that he (Biden) had better polls," Shumilin said.

For Shumilin, Trump remained the Kremlin's favoured candidate as the US president has shown that "he is not ready to strengthen sanctions and even tried to soften them".

Trump is not the only factor.

The US Congress -- where the Democrats have the majority -- has also been making life difficult for the Kremlin by imposing sanctions.

In the end, "Trump or Biden -- I don't think there is a favourable prospect for Russia," said Lipman.

This was echoed by Foreign Minister Sergei Lavrov in an interview with Russian-language TV channel RTVI: "We realise that there will be no major changes in our current relations either with the Democrats or with the Republicans."

Moscow could benefit from a political crisis in the US, for example in the event of Trump refusing to accept the result, something he has repeatedly evoked.

This scenario was also mentioned by Lavrov.

"We would not like to see such a leading global power, like the United States, fall into a deep crisis if new disturbances are added to the current manifestations of violence and racism," he said, quoted by TASS news agency.

For Lipman, "post-election chaos" has great appeal for the Kremlin.

"The United States will be focused on its own affairs and not on Russia. And (Moscow) will make use of this".