Najjar said he phoned Malik prior to his departure, calling on him to hand over Sunni militants with the Jundallah organization connected to a weekend attack in the border province of Sistan-Baluchistan.
Jundallah claimed responsibility for an attack that left scores dead, including senior commanders of Iran's elite Revolutionary Guard Corps.
Iran blames Pakistan for the attacks but singles out the United States as a source of support for the Sunni group. Jundallah is not listed on the U.S. State Department list of foreign terrorist organizations.
"This is not the first time the terrorist cell have committed crimes," said Najjar. "The Iranians are wondering how such a group (could) easily commute in the neighboring Pakistan's soil."
Jundallah claimed responsibility for a June attack at the Ali Ibn Abi Taleb mosque in Sistan-Baluchistan province that killed as many as 21 and wounded more than 70 others.