QUETTA, Pakistan (Reuters) -- Pakistani security forces have arrested three Iranians suspected of planning a suicide attack in Iran's southeastern region last month that killed 42 people, officials said.
Mainly Shi'ite Iran says the Sunni rebel group Jundallah (Soldiers of God), which has claimed responsibility for the October 18 attack, operates from across the border in Pakistan.
The attack in Iran's Sistan-Baluchistan Province killed 15 Iranian Revolutionary Guards, including six senior commanders, and 27 others.
The ethnic Baluch men were arrested by the paramilitary Frontier Constabulary troops in a raid on November 5 in Turbat, a district in Pakistan's southwestern Baluchistan Province on the Iranian border, intelligence and paramilitary officials said.
"They are Iranian Baluch and are suspected to be involved in the planning of the suicide bombing in Iran last month," an intelligence official told Reuters on condition of anonymity. He gave no further details.
The arrests came two weeks after Iranian Interior Minister Mostafa Mohammad Najjar visited Pakistan to demand it hand over Abdolmalek Rigi, the militant group's leader.
Pakistan has condemned the bombing and vowed to help Iran track down those responsible, but says Rigi is in Afghanistan, according to their information.
After the attack, Pakistani President Asif Ali Zardari and his Iranian counterpart, Mahmud Ahmadinejad, spoke on the telephone and stressed the need for cooperation in confronting and eradicating "criminal terrorists."
Pakistan launched a long-awaited offensive against militants in its northwest on October 17 after a string of bomb and suicide attacks rocked the country, including one on the army's headquarters early that month.
Iran-Pakistan ties have generally been good recently, but tension has risen since Iran said the October attack would affect relations and some Revolutionary Guard commanders have said they should be able to pursue Jundallah in Pakistan.
Iran accuses the United States and Britain of backing Jundallah and has suggested it has links with Pakistani intelligence. Washington, London and Islamabad have all denied involvement.