Users trying to reach Twitter early Friday were redirected to a Web page that had a picture of a green flag and a message that said, "This site has been hacked by the Iranian Cyber Army."
There was no evidence the hackers are actually linked to Iran, but another site, mawjcamp.org, which publishes news favorable to the Iranian opposition, was also hacked and remains down.
Last June, Web sites like Twitter and Facebook brought attention to Iranian street protests after anger erupted over a contested presidential election and the violent crackdown that followed it. The Iranian government tried to block media coverage of the chaos, but Twitter and Facebook users found ways to distribute minute-by-minute updates and amateur video that included a young woman's death.
Twitter later Friday posted a message on its blog that said its Domain Name Systems' records "were temporarily compromised but have now been fixed." The site says it will update with more details "once we've investigated more fully."
The top of the graphic says in large English letters:
Iranian Cyber Army
THIS SITE HAS BEEN HACKED BY IRANIAN CYBER ARMY
At the bottom in small letters it reads:
U.S.A. Think They Controlling And Managing Internet By Their Access, But THey Don't, We Control And Manage Internet By Our Power, So Do Not Try To Stimulation Iranian Peoples To….
NOW WHICH COUNTRY IN EMBARGO LIST? IRAN? USA?
WE PUSH THEM IN EMBARGO LIST
The image contains two pieces of Arabic writing. In large blue letters, it says: "Verily, the Party of God (believers) will be victorious." The line, which is taken directly from the Koran, could be a reference to Hezbollah, the Iranian-backed militia in Lebanon, whose name literally means "Party of God."
A second piece of Arabic writing is in small red letters on a large green flag. It says: "Peace be Upon Him."
Below it in large Farsi letters is a reference to Imam Husayn, a highly revered religious figure for Shiite Muslims. Shiites are the largest Muslim sect in Iran.
The bottom of the graphic contains a Persian poem written in Farsi:
At our leader's command, we fight / gallop
At his demand we fall on our swords
If he asks us to remain calm and patient
We'll be patient, even if we burn and perish in submission