(CNN) -- The Syrian Electronic Army, a group of pro-Syrian regime hackers that has aggressively targeted major news organizations and activists, has claimed credit for a 20-hour-long outage of the New York Times website. Several Twitter users posted screenshots of a "Hacked by SEA" message they said they received when they went to the New York Times homepage Tuesday. It's not the first such action by the group; in recent months, it claims to have hacked major UK and U.S. news organizations, as well as Columbia University and rights group Human Rights Watch. CNN.com has been the target of similar attacks.
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The Syrian Electronic Army has claimed an attack on the New York Times website
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The attack is a "serious escalation" in the group's operations, says a researcher
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It's targeting U.S. and European media perceived as hostile to Syria's government, he says
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An attack on the AP Twitter feed caused a flurry of panic and sent stocks plunging
And it may operate in cyberspace, but its attacks can have real-life impact, as was shown when the group hacked the @placeholder Twitter feed in April.