BANGKOK, Oct. 3 — It was about as simple and uncomplicated as shooting demonstrators in the streets. Embarrassed by smuggled video and photographs that showed their people rising up against them, the generals who run Myanmar simply switched off the Internet.

Until Friday television screens and newspapers abroad were flooded with scenes of tens of thousands of red-robed monks in the streets and of chaos and violence as the junta stamped out the biggest popular uprising there in two decades.

But then the images, text messages and postings stopped, shut down by generals who belatedly grasped the power of the Internet to jeopardize their crackdown.

“Finally they realized that this was their biggest enemy, and they took it down,” said Aung Zaw, editor of an exile magazine based in Thailand called The Irrawaddy, whose Web site has been a leading source of information in recent weeks. The site has been attacked by a virus whose timing raises the possibility that the military government has a few skilled hackers in its ranks.