Judicial spokesman Jamal Karimi Rad was quoted today as saying six suspects were arrested yesterday on suspicion of involvement in the blasts, at least one of them over the Tehran bombing.
He gave no details on the suspects' identity.
Iranian intelligence chief, Ali Yunessi, late yesterday said "several suspects" had been arrested, and he claimed they were "linked to elements abroad."
Meanwhile, there were at least two small explosions in the southeastern city of Zahedan late on Monday and early today. Two people were reported slightly injured.
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See "Iran Votes 2005" for full coverage of Iran's 17 June presidential election.