Two men found guilty of bomb attacks in the south-western Iranian city of Ahwaz in 2005 have been publicly hanged, at the place where the bombings occurred.
The executed bombers appeared on TV confessing to the attacks
Local news agencies said onlookers shouted anti-American and anti-Israeli slogans as the two men were executed.
Six people were killed and many more injured in the bombings, which some Iranian officials have blamed on UK forces stationed in southern Iraq.
Britain has strongly denied any involvement in the bombings.
The New-York-based group Human Rights Watch said earlier this week that the number of executions being carried out in Iran has risen dramatically since the election of President Mahmoud Ahmadinejad last year.
On the eve of their execution, the bombers were shown confessing on provincial television, the BBC's Frances Harrison reports from Tehran.
One of those now executed, Ali Afravi, said he had contacted Arab separatist groups based in Canada and Britain after reading their websites.
He said these groups asked him to create insecurity inside Iran.
In total, nine men were shown on TV making confessions that were heavily edited. It is not clear what will happen to the rest who were tried and convicted behind closed doors.
The attacks were part of a series of bombings in the city of Ahwaz, in Khuzestan province, following unrest a year ago in which ethnic Arabs protested against alleged discrimination by the Persian majority.
Khuzestan television showed footage of the bombings that indicated the damage was far more extensive than reported at the time.
Although several Iranian officials have blamed the bombings on British forces stationed just across the Iran-Iraq border, the televised confessions made no reference to such allegations.