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A hack of Democratic party emails has been blamed by Hillary Clinton's campaign team on Russian agents trying to help Republican Donald Trump. So are there really any links between the New York hotel developer and Moscow?

Several pundits have raised questions about the businessman's ties to Russia, amid fears that Moscow could be interfering in the US election.

Russian Foreign Minister Sergey Lavrov has strongly rejected the accusation that Russia was responsible for the hack.

"I don't want to use four-letter words" he said, when asked about the allegation.

So what links are there between Mr Trump and Russia?

1. The email hack

The Democratic convention was supposed to be a seamless show of unity. But a data dump of Democratic National Committee emails has caused chaos in Philadelphia.

The New York Times later reported that "researchers have concluded that the national committee was breached by two Russian intelligence agencies".

According to the Daily Beast: "It's an operation that several US officials now suspect was a deliberate attempt to influence the presidential election in favor of Donald Trump."

Trump and his aides have denied any connection, and there is no evidence linking Trump to the leak.

"The new joke in town is that Russia leaked the disastrous DNC e-mails, which should never have been written (stupid), because Putin likes me," Trump tweeted.

On Wednesday, however, he called on Russia to find emails deleted from Clinton's private server. "Russia, if you're listening, I hope you'll be able to find the 30,000 emails that are missing," he said at a press conference. "I think you will probably be mightily rewarded by our press."

2. Pro-Putin staff

Image copyright Getty Images Image caption Paul Manafort worked closely with Pro-Putin politicians in Ukraine

Paul Manafort, Trump's campaign chairman, has spent decades as a political adviser in eastern Europe.

Mr Manafort worked closely with former Ukrainian President Viktor Yanukovych, who was ousted from power in 2014 and is a known ally of Vladimir Putin.

According to Josh Marshall, one of the most vocal journalists questioning Mr Trump's Russian ties, his foreign policy advisor Carter Page has "deep and continuing financial and employment ties" to Gazprom, Russia's trillion dollar energy company.

"It is no exaggeration to say that you cannot be involved with Gazprom at the very high level which Page has been without being wholly in alignment with Putin's policies," Marshall writes.

But in a critical response to Marshall, author Jeffery Carr notes that Mr Page "left Gazprom in 2007 and has made very little money from Russia ever since".

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3. Changes to Republican manifesto

The Republican National Committee shifted their stance on Russia under pressure from Trump staff in the days leading up to the convention in Cleveland last week.

One delegate proposed an amendment calling for the US to provide eastern Ukraine with "lethal defensive weapons" in their ongoing struggle with Russian-backed rebels in the region.

According to the Washington Post, Trump's allies pushed to weaken the statement, committing instead to providing "appropriate assistance".

It was the only substantial change to the platform that Mr Trump's team requested, and it came as he told the New York Times that he might not honour Nato commitments should Russia invade Baltic states.

Still, the Post also notes that such a position, while out of step with basic Republican tenets, is not unheard of in Washington:

"President Obama decided not to authorise [sending lethal weapons to Ukraine], despite recommendations to do so from his top Europe officials in the State Department and the military."

Image copyright Getty Images Image caption Putin described Donald Trump as talented and outstanding

4. Financial ties

Mr Trump no longer does business with many US banks. Instead, Marshall argues, Trump "has steadied and rebuilt his financial empire with a heavy reliance on capital from Russia".

That includes "financing from questionable sources in Russia and Kazakhstan," according to a lawsuit uncovered by the New York Times.

Mr Trump himself has said he has "zero investments" in Russia.

And as Julia Ioffe writes in Foreign Policy, many companies pursued business in Russia, and Trump failed to make significant inroads in the country.

"The fact that Trump, after so many attempts and with such warm intentions toward the country, was not able to build anything in Russia- when Ritz Carlton and Kempinski and Radisson and Hilton and any number of Western hotel chains were able to - speaks to his abysmal lack of connections to influential Russians," she writes.

It's not unusual for real estate companies to receive significant Russian business but there's no evidence that Trump's political views have been bought.

"Correlation does not prove causation. Just because funders might want to influence powerful people doesn't mean that they actually do," writes the Washington Post's Daniel Drenzer.

Image copyright Getty Images Image caption A mural in Lithuania shows Trump and Putin kissing

5. 'Bromance'

Putin called Trump "bright" and "very talented". Trump has spoken with admiration on multiple occasions about Putin's political strength.

"What we have is a kind of bromance going on between Vladimir Putin and Trump," Clinton advisor Jon Podesta said on TV when asked about the email hack, noting there was no known connection between the two.

President Barack Obama told NBC he did not know if the hack came from Russia but added: "What I do know is that Donald Trump has repeatedly expressed admiration for Vladmir Putin.

"And I think that Trump's gotten pretty favourable coverage back in Russia."

Ioffe has reported that the Kremlin dislikes Clinton and sees a Trump presidency as one more aligned with their interests.

But that doesn't meant Mr Trump is in cahoots with Mr Putin. It is not illegal to speak glowingly of an American adversary, or to share similar political values.

Judging by the latest polls, it's not a deal breaker for American voters, either.