At least four people were killed on Tuesday in a double bomb attack in the southwestern Iranian city of Ahvaz, capital of oil-rich Khuzestan province, state television reported.
The official news agency IRNA reported that the first bomb exploded close to a bank, and a second in front of an official building dealing with natural resources.
Situated close to the border with British-controlled southern Iraq, Ahvaz has been hit by a wave of deadly unrest over the past year.
Iran was hit by riots in April 2005 and a string of car bombings prior to its presidential election last June.
The area is dominated by ethnic minority Arabs.
Iran has pointed the finger of blame at Britain, which has angrily denied any involvement and which has in turn accused of Iran of being linked to unrest inside Iraq.