These arsenals have been confiscated during a raid on the hideout of a terrorist group known as Jondollah in the provincial capital city of Zahedan on Thursday.
A bomb blast tore through a bus in Zahedan, southeast Iran at 06:10 (2:40 GMT) on Wednesday, killing 12 people and wounding 31 others.
The bus belonged to the Zahedan branch of the Islamic Republic's Mobilized Forces (Baseej), and the passengers were all members of the ground force of the Islamic Revolutionary Guards Corps (IRGC).
Earlier a source said that the relevant documents, photographs and film footages showing that the explosives and arsenals used in the attack were American would be presented to the public and media in the near future.
He further pointed out that the terrorist group 'Jondollah' had several plots for assassinating Sunni and tribal leaders to sow discord and foment conflicts between the Shiite and Sunnite citizens in Sistan and Balouchestan province.
Iran on Saturday invited international bodies to send envoys to Tehran to witness documents and other corroborative evidence showing involvement of foreign countries in recent terrorist blasts in the country's southeastern provincial capital city of Zahedan.
Director General for the political affairs of Sistan and Balouchestan governorate Soltan-Ali Mir told FNA that the US and Britain are behind the recent terrorist attacks in the city of Zahedan, adding, "Washington and London are facing serious challenges as their interests in the Middle-East region have been endangered. Since the Islamic Republic is the main center of anti-US struggles, they are seeking to trouble Iran through a series of challenges, including terrorist attacks and unrests."
Asked to elaborate on the documents proving involvement of the US and Britain in recent incidents in Iran's Sistan and Balouchestan province, he said, "The weapons that the terrorists have used are US and British made. Moreover, the arrested terrorist agents have confessed that they have been trained by English-speaking people."
The official invited representatives of the United Nations, Human Rights watch and other international bodies to dispatch envoys to Iran to observe the available documents and proofs substantiating involvement of the Untied States and Britain in the recent terrorist attacks, including the blast and shootout on Wednesday.
"The US and Britain, which allege to be pioneers in the campaign against terrorism, are themselves actually defending the terrorists, training them and providing them with the needed media and financial supports and facilities," he added.
Soltan-Ali Mir further pointed out that the US and Britain intend to create a series of incidents in his province similar to what they have already done in Iraq.
"They intend to kill the Shiites and leave the footsteps at the door of the Sunnis or vice versa. Some of the arrestees confessed that they had plans to assassinate religious and tribal leaders of the Sunnis and put the blame on the Shiites in a bid to foment ethnic and religious conflicts," he stated.
The official also noted Iran's good and friendly relations with the neighboring countries, and said that Iranian and Pakistani officials will soon attend meetings to improve security at the borders.
Meanwhile, he called on the security officials of Iran's eastern neighbors to take the required precautions to secure their joint borders with Iran, saying that it is now the Islamic Republic which is paying a heavy price for securing the borders and that neighboring countries should enhance their efforts to prevent terrorists from trafficking across the border.