It is almost impossible to know for sure whether or not Russia is behind a hack of the Democratic National Committee's servers, says security expert Andrei Soldatov. The finger of blame has been pointed at Russian state hackers by members of Hillary Clinton's team following the dumping online of more than 19,000 DNC emails by WikiLeaks. The emails show apparent favoritism towards Hillary Clinton over Bernie Sanders as the Democratic presidential nominee.

The claims that her team and security experts make are staggering: that Russian state hackers attacked the DNC's servers to undermine Clinton's campaign to become president in order to boost Donald Trump.

The Kremlin has denied the suggestion, calling it "absurd."

President Putin's spokesman Dmitry Peskov said, "Moscow has carefully avoided any actions, any words that could be interpreted as direct or indirect influence on the electoral process."

Russian Foreign Minister Sergei Lavrov said, "I don't want to use four-letter words" when asked about alleged Russian involvement by reporters during a meeting with US Secretary of State John Kerry.

The attack is currently being investigated by the FBI and although neither the White House nor the State Department have accused Russia of the hack, President Barack Obama has said "anything is possible," when it comes to Russian involvement.

"What we do know is that the Russians hack our systems, not just government systems but private systems," President Obama said.

Hacking to lift sanctions

There are several reasons why Russia would try to sway the outcome of the US presidential election in November, not least because the Kremlin considers Clinton "a hater of Russia," says Soldatov. Soldatov is a Russian investigative journalist, expert on the Russian security services and co-author of The Red Web, a book on how the Kremlin controls the Russian internet.

"The elections in the United States are really, really, really important for Russia," he stressed.

"[The Kremlin] believes that with Clinton in the White House it will be almost impossible to lift sanctions against Russia. So it is a very important question for Putin personally. This is a question of national security."

Russia has been under economic sanctions from the EU and the United States since 2014 after it annexed Crimea from Ukraine.

Vladimir Putin has previously accused the United States of meddling in Russian affairs by stoking so-called 'color revolutions' in former Soviet states and by fueling protests against him in Russia during the winter of 2011-2012.

"You do not need any justification [for the attack] in this climate of paranoia," Soldatov said.

"There is this mentality in Russia of being besieged; that it is always under attack from the United States," he said. "They are trying to interfere in our internal affairs so why not try to do the same thing to them?"

Breach detected in April

The security firm CrowdStrike uncovered a suspected breach of the DNC in April and says it identified "two sophisticated adversaries" whom it linked to Russian intelligence.

Soldatov says the attack has parallels to the hacking of a power plant in Ukraine in December where two teams were also used. He says, however, that the Russian intelligence services themselves may not be directly tapping the keys when hacking organizations like the DNC.

"We tend to have this picture that our intelligence agencies have these capabilities and that they should be behind it. The truth is that, in many cases, it is not state agencies which are behind it but rather groups of hackers funded or supported by the political wing inside the administration of the president."

This, he says, is "more convenient" as there are pro-Kremlin youth movements to which the Kremlin will "channel money uncontrolled." Then, he says, it is just a matter of asking "some people inside the youth movement to find some good, professional people to do the hacking."

'Impossible the Kremlin did not know'

It raises the question of whether the Kremlin was actually aware of the alleged Russian hack on the DNC, or whether, as Soldatov suggests, it funded a group of hackers who took it upon themselves to attack the Democratic Party.

"It's impossible that the Kremlin did not know what is going on," he said. "This is not some Russian opposition leader, who might be hacked. This is a question of the utmost importance to Russia."

US-Russia 'reset'

It is very likely that a 'President Trump' would take a considerably warmer approach towards Russia than his Democratic predecessors.

Donald Trump has often praised President Putin and has called him a "strong leader." He - like Vladimir Putin - is a critic of NATO and recently suggested he would defend NATO allies only after assessing whether they "have fulfilled their obligations to us."

Vladimir Putin for his part has said that Donald Trump is a "very striking man, unquestionably talented." He also said that "Mr Trump has said that he is ready for a full-scale revival of Russian-American relations. What's wrong with that? We welcome that."

While Soldatov says the perceived connection between Donald Trump and Vladimir Putin is "too good to be true", he says he believes the Kremlin is trying to "make things harder for Clinton."

The concern now for the Democratic Party is what else might come from the leak. In an interview with CNN, WikiLeaks founder, Julian Assange, said the organization might release "a lot more material" relating to the Democratic campaign.

According to Crowdstrike, hackers were able to access DNC servers for months. There is the possibility, therefore, that in the months leading up to the November election more emails could be released. These could have the potential to cause even more damage to Clinton's campaign - and boost that of her rival, Donald Trump.