A little-known Iranian Sunni dissident group says it was behind a deadly mosque bombing in southern Iran, which Tehran blames on the United States, Britain, and Israel, according to an internet statement. "This is the very first operation and the signal to the criminal regime of Iran ... to stop its oppression, cruelty and injustice towards ... Sunnis," The Jihadi Movement of the Sunna People of Iran said. The group said it carried out the attack, which killed 14 people in the southern city of Shiraz in April, to avenge what it said was the execution of two Sunni scholars in Iran's poor southeastern region, home to mostly Sunni ethnic Baluchis. The English-language statement, posted on a website linked to Sunni Muslim dissidents, could not be independently authenticated. Iran said last month it arrested the group behind the attack and protested to Washington, saying the US had supported the attackers. It said the group also planned to blow up oil pipelines. President Mahmoud Ahmadinejad has accused the United States, Israel and Britain of being responsible for the blast. In April when an Arabic website said the Jihadi Movement was behind the attack, Iran said the blast was an accident. The latest claim was accompanied by a video showing the moment of the attack in the crowded mosque, which had been issued on the internet two months ago, and apparently recorded by someone not involved in the attack. The group added Islamic chants to the video, as well as warnings of more attacks.