Bombs exploded in Iran, in the southwestern city of Ahwaz and in Tehran.
Ahwaz saw some Arab-Persian violence earlier in Spring, following rumors of attempts to load the city with non-Arabs.
Government spokesman Agha Mohammadi was pretty liberal in spreading the blame:
A spokesman for the Supreme National Security Council, Iran's top security decision-making body, blamed the attacks on separatist Arabs aided by members of the armed Iraq-based opposition group, the People's Mujahideen, and remnants of the Baath Party.
The spokesman, Agha Mohammadi, told the BBC he was sure the Americans were behind the attacks and also suggested that Britain might be involved - but he gave no evidence to support his claims.
Beware the highly improbable American-Baathist alliance against Iran (NB: not improbable at all in the 80s when we did just that, but fairly unlikely now).