Ustream was taken down by a DDoS attack earlier today that appeared to be intended to disrupt live streaming of video from anti-government demonstrations in Russia.

"Ustream believe the DDoS attack started around 5.30am ET (2.30pm Moscow Time), and involves thousands of IP addresses, largely from Russia, Kazakhstan, and Iran," writes Business Insider's Adam Taylor.

"Around 9:30 a.m. PT the Ustream account on Twitter reported that 'Our heroic engineers have partially restored (the) streaming service after DDoS attacks on Russian Citizen Journalist,'" writes CNET News' Elinor Mills.

"A Ustream spokesperson says that the attacked is targeted on user reggamortis1, a prominent protestor’s live Ustream channel," writes TechCrunch's Ingrid Lunden. "'He has been broadcasting from a large protest at the 'China Town' metro stop in Moscow.' Ustream says that this is the third major DDoS attack on Ustream in the last six months related to a Russian citizen journalist, and the biggest DDoS attack it has ever had."

"Ustream has become a highly popular way of chronicling the ongoing street protests against the Putin regime in Russia, which are not covered in the mostly state-controlled media," write The Daily Beast's Ben Jacobs and Anna Nemtsova. "At one point, at a protest on December 6, 2011, over 500,000 people in Russia alone were watching one particular live stream of a protest. The website has been used to chronicle protests in other countries, including the Arab Spring protests of 2011 in Tunisia and Egypt."