TWO leading dissident Burmese websites have been shut down by a sophisticated cyber attack believed to have been initiated by the military junta a day before the first anniversary of Burma's so-called Saffron Revolution.

The websites, run by the Democratic Voice of Burma and The Irrawaddy news magazine, are operated by exiles in Norway and Thailand respectively. Both were disabled on Wednesday.

Inside Burma, internet services were reportedly running slowly, suggesting an attempt by the regime to stem the flow of information in and out of the country at such a sensitive time.

The internet played an essential role in last year's uprising, when thousands of Buddhist monks led mass protests through the streets of Rangoon. Citizen journalists flooded dissident websites abroad with hundreds of images, videos and reports and subsequent crackdown, until the military shut down the service on September 28. The Irrawaddy's editors learnt access to the website and a mirror site on a separate server had been blocked on Wednesday after subscribers in the US, Japan and Malaysia complained they could not access the websites.

The Irrawaddy was told by its service provider the website was under a "very sophisticated" cyber attack. An editorial by its editor, Aung Zaw, said Burmese authorities had in recent years sent students to Russia for cyber-warfare training and paid hackers overseas to target the exiled media websites.