Media playback is unsupported on your device Media caption John Dean spoke to BBC radio about Watergate

The row over the US attorney general's denial that he met a Russian official when he had in fact done so is leading to comparisons with the most notorious political scandal in US history - Watergate.

The events of 1972 led to the downfall of President Richard Nixon, who resigned after a web of political spying, sabotage and bribery was exposed by the media.

Among the most prominent voices linking Trump and Watergate is Nixon lawyer John Dean, then described by the FBI as the "master manipulator of the cover up".

"I have been hearing echoes of Watergate ever since this presidency started," he told the BBC.

"We are not at Watergate 2.0 yet but we are certainly seeing trends and [Jeff] Sessions dissembling in front of the Senate is just another one."

Mr Trump himself has also taken to referencing Watergate, though not for the same reasons. In a tweet he accused Barack Obama of tapping his phones in during the election, sparking a new row.

What happened during Watergate?

The name, Watergate, refers to an office and hotel complex in Washington where five men were arrested in June 1972 trying to bug the offices of the Democratic National Committee (DNC).

Image copyright AP Image caption Nixon became the only US president to resign from the job

The break-in was traced to Nixon supporters. The Senate investigated and in April 1974 President Nixon released edited tapes of his conversations about Watergate. In July the Supreme Court ordered Nixon to hand over the tapes and the House of Representatives Judiciary Committee approved impeachment.

In August, Nixon admitted he had been aware of the cover-up and had tried to halt the FBI's inquiry. Four days later, he became the only US president to resign.

But are there really parallels between the Trump administration's alleged links to Russia and what happened 45 years ago?

DNC targeted

One similarity is that the DNC, the target of the Watergate break-in, was also targeted in last year's US election campaign, when emails were stolen and leaked.

US intelligence agencies say Russia was behind the DNC hack, though Russia denies any involvement.

Russia is believed to have wanted Mr Trump to win the election. An unverified report apparently compiled by a private intelligence firm claimed Russia had compromising information on Mr Trump and was in a position to blackmail him.

Some commentators - including former President George W Bush's ethics lawyer Richard Painter - now fear the Russian connection could make Watergate seem trivial.

Media playback is unsupported on your device Media caption Jeff Sessions: "I have recused myself in the matters that deal with the Trump campaign"

"The facts now in this investigation are much worse than the facts in the early stages of Watergate, which was a simple break-in ordered by mid-level campaign officials - not by the president," Mr Painter told Vox.

"Here we have facts that are much worse: We have a foreign power that has orchestrated a break in. It's a much worse situation than the outset of Watergate."

Attorney generals under scrutiny

The alleged falsehood told by Mr Sessions has also fired up Watergate comparisons.

One of Mr Nixon's attorney generals, John Mitchell, was later jailed for offences including perjury for his role in the scandal.

Image copyright @JohnWDean

Image copyright @RWPUSA

His replacement Richard Kleindienst was not implicated in Watergate but pleaded guilty in 1974 to failing to testify fully to the Senate about favouritism shown to a communications company during his confirmation hearing.

"It's pretty clear listening to his testimony that [Sessions] certainly wasn't truthful when he was before the Senate and I don't think that's simply going to disappear because he's recused himself from partaking in any of the investigation as attorney general. That's going to continue," Mr Dean said.

"These eerie echoes of Watergate keep coming," he added.

'What did the president know, and when did he know it?'

Mr Sessions is now facing calls for him to quit over his recently-admitted contact with Sergei Kislyak - the same Russian official whose phone calls with Mr Trump's former national security adviser Michael Flynn led to Mr Flynn's resignation last month.

Mr Flynn's exit prompted veteran journalist Dan Rather to say on Facebook: "Watergate is the biggest political scandal of my lifetime, until maybe now."

Image copyright AP Image caption Contact with Mr Kislyak has already seen Mr Flynn resign - will it do the same for Mr Sessions?

It is alleged that Mr Flynn discussed diplomatic issues with Mr Kislyak before assuming his role at the White House. It is illegal for private citizens to conduct US diplomacy.

Some commentators are now calling for a Watergate-style bipartisan Senate select committee to investigate links between Mr Trump's administration and Russia.

"I would immediately get a special prosecutor on the case," said Mr Dean.

Mr Trump's January dismissal of the previous attorney general Sally Yates also led to comparison's with Nixon's infamous "Saturday night massacre" during Watergate in 1973, when he fired an independent special prosecutor, triggering the resignations of attorney general Elliot Richardson and his deputy Gen William Ruckelshaus.

Nixon and Mr Trump are believed to be the only US presidents to have dismissed an attorney general.

Trump fires back

As more people began making comparisons between the Trump administration and Watergate, Mr Trump took to Twitter to accuse Mr Obama of Watergate-style behaviour and call him a "bad (or sick) guy".

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The allegation - which Mr Trump has not provided evidence for - has further convulsed US politics, with Mr Obama denying it and FBI director James Comey also reportedly denying it.

Mr Comey has also reportedly asked the US Justice department to reject the allegation because it suggests that the FBI acted illegally.

The White House has also called on Congress to investigate whether the Obama administration abused its powers.