Hacking: A thorny issue between Russia and the West
Russian hackers have been accused by the United States of carrying out a series of attacks against political organisations in order "to interfere with the US election".
State involvement remains of a matter of debate. Russian officials have strenuously denied having anything to do with the hacks.
In an earlier incident, Democratic nominee Hillary Clinton said her party had been targeted, and Defence Secretary Ash Carter warned Russia against "interfering with democratic processes".
The developments came in the wake of reported hacking of voter databases in two US states. The FBI is also investigating whether Russian hackers attacked the New York Times.
Such claims are by no means new.
Previous suspected attacks
Suspected Russian cyber attacks against political opponents abroad go back at least a decade, and usually coincide with times of particular tension in relations.
In spring 2007, Moscow was infuriated by the removal of a Soviet monument from central Tallinn, the capital of Estonia. Soon afterwards, Estonian government, banking and media websites came under sustained attack. A pro-Kremlin youth activist claimed responsibility for what he described as a private act of "civil disobedience" carried out in protest at the alleged violation of the rights of Estonia's ethnic Russians.
US diplomatic cables leaked by WikiLeaks described Estonia as an "unprecedented victim of the world's first cyber attacks against a nation-state".
The following year, several Georgian government websites were hijacked in the run-up to and during the Russian-Georgian war in August 2008. The Georgian foreign ministry then accused Russia of waging "a campaign of cyber warfare".
Ukraine, another post-Soviet state that has had troubled relations with Russia and is now in effect at war with its neighbour, has been the target of such attacks too.
The biggest cyber-attack on Ukraine took place on 23 December 2015, when hackers took control of the power grid in western Ivano-Frankivsk region, leaving tens of thousands of people in the dark. According to Wired magazine, it was the first-ever confirmed cyber-attack aimed at taking down a power grid. It also said that the hack involved a telephone denial-of-service (TDoS) attack that appeared to come from Moscow.
The Ukrainian government in Kiev pointed the finger of blame at Russia. SentinelOne, a US-based cybersecurity start-up, said the attack was part of "a nation-sponsored campaign".
Cyber-attacks on Western organisations
More recently, Western organisations too have experienced similar attacks. This is happening at a time when Russia's relationship with the West is at its lowest since the end of the Cold War over the conflicts in Ukraine and Syria.
Last May, Germany's domestic intelligence agency (BfV) reported what it believed was an attempt to sabotage Germany's political internet infrastructure. The head of the BfV said the agency had "indications it [the attack] is being steered by the Russian state".
In August 2016, the World Anti-Doping Agency (Wada) said hackers had accessed personal records of Russian athlete Yulia Stepanova, who blew the whistle on large-scale doping in Russia.
Russia denies interference in US election
Russia has in the past largely ignored accusations of state-sponsored hacking. However, it has strongly and repeatedly denied the recent US statements about its alleged interference in the US presidential election.
"Russia never does this at state level," President Vladimir Putin told Bloomberg news agency.
Foreign Minister Sergei Lavrov described the allegations as nonsense, while ministry spokeswoman Maria Zakharova said that "not once" had America provided facts to support such claims.
Kremlin spokesman Dmitry Peskov said "these statements are still absolutely groundless… they are absolutely unsubstantiated".
Russian information security experts sceptical
Russia's IT and online security community too has taken a sceptical view of claims that the Russian state is engaged in cyber-warfare against its opponents.
Several members of well-known online security firms said these allegations were the result of myths and stereotypes.
"Russian hackers are a myth whose existence is based on political and economic factors," the Russian online technology magazine CNews quoted the head of Informzashchita information security firm, Yevgeny Klimov, as saying.
This "classic stereotype of the 1990s and early 2000s... is widely used for propaganda purposes", Artyom Baranov, an information security analyst from the Slovak-headquartered IT security firm ESET, told CNews.
And Alexander Gostev of Kaspersky Lab said attacks by "Russian-speaking cyber criminals" from the former Soviet republics are often wrongly attributed to Russia.
Kaspersky Lab itself has been accused of links to Russian intelligence services. The founder of the firm, Eugene Kaspersky, denied this, however, saying his company was "1,000 per cent transparent and honest".