Microsoft claimed Tuesday that Russian government-linked hackers targeted US political organizations ahead of midterm elections, drawing a swift denial from Moscow.

The world's largest software company said that a Kremlin-linked cyber group had created fake websites designed to mimic those of two conservative organizations, the DC-based International Republican Institute and Hudson Institute think tank.

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Three other web domains were meant to look like US Senate websites and another mimicked Microsoft's Office 365 product. 

The International Republican Institute promotes international democracy and its board of directors includes six Republican senators and a senatorial candidate. The Hudson Institute conducts research and holds events on domestic as well as foreign policy and security issues.  

Microsoft seized control of the six fake websites last week, the company's president, Brad Smith, wrote in a blog post. The domains were seized from Strontium, a Russian government-linked cyber group also known as Fancy Bear or APT28.

Smith said Russia has been broadening its cyber activity ahead of midterm elections in November.

"We are concerned by the continued activity targeting these and other sites and directed toward elected officials, politicians, political groups and think tanks across the political spectrum in the United States. Taken together, this pattern mirrors the type of activity we saw prior to the 2016 election in the United States and the 2017 election in France," Smith wrote. 

Smith said there was no evidence the domains were actually used in successful cyberattacks before they were seized, nor was there anything to indicate the exact target of any planned cyberattacks. 

The revelation comes weeks after Microsoft identified suspected unsuccessful Russian cyberattacks on the staff of two senators, including Senator Claire McCaskill, a Missouri Democrat who is running for re-election.

The Russian government responded on Tuesday by saying that it did not understand Microsoft's allegations.

Read more: European Commission warns of 'fake news,' meddling in 2019 European elections

"We don't know what hackers they are talking about," Kremlin spokesman Dmitry Peskov told reporters when asked about Microsoft's accusations.

"Who exactly are they talking about? We don't understand what the proof and the basis is for them drawing these kinds of conclusions. Such information is lacking," Peskov added.

In July, a US grand jury indicted 12 Russian intelligence officers for stealing information on 500,000 voters, as well as hacking Democratic Party computers during the 2016 US presidential election.

US intelligence agencies have said Russian meddling in the US election was meant to undermine faith in democracy, deepen political and social division, and help Donald Trump win the presidency against his Democratic opponent, Hillary Clinton.

law/cw (AFP, Reuters)