Iran's intelligence minister said on Monday that a "large" network of suspects have been arrested in connection with Saturday’s attack on a military parade in the city of Ahvaz that killed 25 people.

"We will identify all terrorists linked to this attack ... A large part of this network has already been arrested," Mahmoud Alavi was quoted as saying by the Iranian media, on the sideline of the funeral of the victims in Ahvaz. He was part of a government delegation taking part in the funeral.

The minister did not provide any details about the identity of those arrested or their affiliation, but vowed tough measures against those committing "such crimes".

Both an ethnic Arab group and the Islamic State Group have claimed responsibility for the attack.