"We can confirm that Twitter was blocked in Egypt around 8 am (Pacific Time, 1600 GMT) today," Twitter confirmed on the @twitterglobalpr feed. "It's impacting both Twitter.com & applications. We believe that the open exchange of info & views benefits societies and helps govts better connect with their people."
According to Herdict.com, which tracks government attempts to block internet sites, Egyptian authorities appear to be taking action against other popular communications sites, too, such as Facebook, YouTube, Person.com and veoh.com. However it appears that such actions have been partially circumvented, because many users in Egypt still reported being able to access the sites, including by mobile telephones.