THE US Ambassador to Russia has quit and urged Donald Trump to hold Vladimir Putin to account in his parting letter.

Jon Huntsman’s resignation signals the end of a two-year stint during a "historically difficult" time in relations between the two countries.

5 Jon Huntsman, the US Ambassador to Russia, has quit Credit: Copyright 2017 The Associated Press. All rights reserved.

5 The diplomat urged Donald Trump to hold Vladimir Putin to account Credit: AP:Associated Press

It comes after reports that Trump and Putin discussed the need for a new US ambassador in Russia while speaking on the phone last week.

In his resignation letter, Huntsman urged Trump to stand up to the Russian President and work to stabilise “years of acrimony”.

“Going forward, we must continue to hold Russia accountable when its behaviour threatens us and our allies,” Huntsman told Trump.

He acknowledged there are “irreconcilable” differences between the two countries, but said there are also common interests.

Huntsman reminded Trump that Russia has a history of disrespecting human rights and violating the sovereignty of its neighbours.

“While times are tough, it is critical that we increase exchanges of people and maintain channels for dialogue on issues of national interest,” he wrote.

These include combatting terrorism and ensuring “verifiable arms control”.

He warned Trump against the kind of “reset” with Russia that humiliated the Obama administration.

“No reset or restart is going to help…Failure is not an option.”

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5 In his resignation letter, Huntsman urged Trump to stand up to the Russian President

In the letter, Huntsman said he was honoured by the trust Trump placed in him "during this historically difficult period in bilateral relations".

During his years as Trump’s man in Moscow, a number of high-profile incidents have strained relations between the US and Russia.

Former Russia spy Sergei Skripal and his daughter were poisoned in Salisbury, UK, with a Novichok nerve agent in March last year.

In the wake of the attempted assassination, Trump ordered the expulsion of 60 Russian diplomats the US identified as intelligence agents.

Moscow responded by expelling the same number of American diplomats.

Huntsman also served as the ambassador during Robert Mueller’s two-year Russia probe.

He revealed in November that he had stage one melanoma - a diagnosis that he did not share with anyone in Moscow out of concern over how the information would be received.

The diplomat said both he and his wife, Mary Kaye, had given the sensitive assignment their best.

The decision comes as the Trump administration is also dealing with the departure of Fiona Hill, the top official on Russian affairs at the National Security Council.

‘CORRUPT’ Putin now so hated that citizens believe Russia was better off during Soviet Union VLADIMIR Putin is now so unpopular that his citizens believe Russia was better off during the dark days of the Soviet Union, a poll has found. Putin, 66, in power as president or prime minister since 1999, was re-elected by a landslide last year but his high ratings have slipped over pension reforms. Some 41% of Russians view the current government as “criminal and corrupt”, with a third of citizens saying it is “distant from the people”, according to a poll. Of those polled, 29% said they thought that the Kremlin in the late 1970s and early 1980s was “close to the people”. Only 8% thought the same of today’s government. The four other main characteristics of the late Soviet era were that its governance was strong, fair, lawful and short-sighted, respondents said. This is despite millions of people getting shot, sent to gulag camps, exiled or perishing in famines under Stalin, who died in 1953.

Huntsman is planning to return to Utah amid speculation that he may again run for governor, said Salt Lake Chamber president Derek Miller, who served under him during his previous tenure.

Huntsman, a Republican, left the Utah governor's office in 2009, when former President Barack Obama tapped him as ambassador to China.

He was popular in the state and had been elected to his second term the year before.

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Huntsman mounted a brief run for president in 2011.

In 2017, President Donald Trump named him as ambassador to Russia, as the US investigated Moscow's meddling in the 2016 election.

Huntsman is expected to stay in the post until October 3.

5 Huntsman during a meeting with Putin at a 2017 ceremony at the Kremlin Credit: Getty - Contributor