Iran has publicly hanged four men convicted of taking part in deadly bombings in the south-western city of Ahwaz last year.
Iran had blamed Britain and its troops for the unrest
The blasts at a bank and the office of the governor killed eight people and injured at least 45 others.
Iran originally blamed British troops based just over the border in Iraq.
Ahwaz, in Khuzestan province, is home to a large community of ethnic minority Arabs and has simmered with anti-government tension since 2005.
The executions were carried out at the city's jail in front of the victims' families.
Last month Iran said it had hanged three people convicted of involvement in the attacks.
In November 2005 protests erupted in Ahwaz after ethnic Arabs accused authorities of discrimination.
Two other people have already been executed over attacks in Ahwaz in October of the same year that killed six people and wounded almost 100 more.