Explosive devices and arsenals used in a terrorist attack in the southeastern Iranian city of Zahedan on Wednesday came from the United States, the semi-official Fars news agency reported on Saturday.

Relevant documents, photographs and film footage, which show that the explosives and arsenals used in the attack were American, would soon be made public, an "informed source" was quoted as saying.

The source further pointed out that Jundallah, a shadowy Sunni militant group, had several plots for assassinating Sunni and tribal leaders to sow discord and foment conflicts between the Shiite and Sunni citizens in Sistan-Baluchestan province.

On Wednesday morning, an explosive-laden car exploded in Zahedan as a bus, belonging to ground forces of Iran's Revolutionary Guards Corps, passed by, killing at least 11 people and injuring 31 others.

Jundallah has reportedly claimed responsibility for the Wednesday attack. Iran has blamed the group for past killings in the area bordering Pakistan and Afghanistan.

So far a total of 65 suspects in addition to the three people responsible for the bomb attack have been arrested, the official IRNA news agency reported Thursday, quoting Brigadier General Mohammad Gaffari, a senior police officer in Sistan-Baluchestan province.

Jundallah also claimed responsibility for a second bombing on Friday in Zahedan, which caused no casualties.