Tehran said this week more could be done by the Pakistanis when it comes to securing the southern border with Iran.
Jundallah claimed responsibility for a blast last week that killed at least 38 people at the mosque in Chabahar, a mainly Sunni city, on the eve of the Shiite holy day of Ashura.
Jundallah, which the United States has designated a terrorist organization, has carried out several high-profile attacks, including violence at mosques and gatherings of Iran's Republican Guard.
A senior Pakistani official told London's pan-Arab daily Asharq al-Awsat on condition of anonymity that intelligence sharing between the two countries had increased since February.
"The Iranian government has recently given us a list of terrorists and fugitives wanted by the Iranian government," the official added.
Iran executed Jundallah leader Abdolmalek Rigi in June.
The Pakistani official told the newspaper the arrest of Jundallah's leader "would not have taken place had the Pakistani intelligence services not tipped off their Iranian counterpart."
Several other members of Jundallah were executed this week for carrying out terrorist attacks in Sistan-Baluchistan province.