Widespread internet attacks that hit services at Google, Facebook and Twitter on Thursday could have been the result of an online assault against a single blogger.

According to senior industry figures, the strikes that affected hundreds of millions of web users around the globe on Thursday were part of an attempt to damage just one individual - a controversial Georgian known only as Cyxymu.

Max Kelly, Facebook's chief security officer, told CNet news that the strike was an attempt to silence Cyxymu - an outspoken critic of last year's conflict between Georgia and Russia in South Ossetia - as the anniversary of the war approaches.

"It was a simultaneous attack across a number of properties targeting him to keep his voice from being heard," Kelly said. "We're actively investigating the source of the attacks and we hope to be able to find out the individuals involved in the back end and to take action against them if we can."

The strikes appeared to be one of the most widespread and coordinated attacks ever seen online, shutting down Twitter for significant portions of Thursday, as well as causing serious problems for Facebook and blogging service LiveJournal. Google, too, was subjected to attacks but said it had been able to prevent any damage - although some users reported some unexpected problems with the internet giant's services.

It is not clear precisely how the attacks started or who was behind it, but a vast number of spam messages were also sent out simultaneously mentioning the victim.

With a monicker styled after the cyrillic name for the disputed Black Sea city of Sukhumi, Cyxymu runs a blog written in georgianised Russian and subtitled "of Sukhumi, the war and Bolivia".

In the past, it was a home for controversial opinions on the way the conflict was handled by both the Russian and Georgian governments - last year resulting in a similar attack by opponents which had crashed LiveJournal.com.

Like many internet users, Cyxymu has accounts across a number of social networking services, and yesterday appeared to recognise that he or she may have been a target.

"It became clear that it is a special attack on me or on Georgians," Cyxymu said in one message. "In my mailbox are hundreds of spam emails."

"Spam was being sent on my behalf with an invitation to go to my blog... I apologise to everyone."

Security experts had already suggested to the Guardian that the widespread and apparently random nature of the attacks could be evidence of a grudge or personal vendetta rather than an organised criminal act aimed at blackmailing major websites.

The war in South Ossetia officially started on 7 August last year, after several weeks of growing arguments over the future of the territory. Following support from Russia, Georgian troops began shelling the town of Tskhinvali. An estimated 25,000 residents of the region were forced to leave their homes as fighting took place, and although the two countries signed a ceasefire agreement a week later, tensions are still high.

At the time, the conflict resulted in an outbreak of hostilities over the internet, with Russian sympathisers attacking Georgian government websites - the same type of attack which appeared to take place on Thursday.