Iranian authorities have arrested 35 people in relation to the January 3 attacks in the southeastern city of Kerman, the Intelligence Ministry said on Thursday, according to the semi-official Tasnim news agency.
The ministry said it had identified one of the two suicide bombers as a national of Tajikistan, who entered Iran illegally on December 19.
More information will be released at a later date about the second suicide bomber, the ministry said, adding that the arrests had been carried out in several Iranian provinces.
The IS claimed responsibility on January 4 for the attack that killed nearly 100 people and wounded 284, at a memorial for top commander Qassem Soleimani.
Tehran has vowed revenge for the bloodiest such attack since 1979.
Israeli airstrikes kill 9 in Gaza, including tent camp, Palestinian officials say
New Zealand braces for more flooding after road collapses, one death
Rubio tells Munich security forum US, Europe belong together
Canadians 'will always be with you' says PM at Tumbler Ridge vigil
UN Chief urges unity as Ramadan approaches
