Two bombs that have exploded in the southern Iranian cities of Dezful and Abadan have wounded at least six people.
The bombs were planted in the governor's office in both cities, which lie in the oil-producing province of Khuzestan. The province has seen ethnic tensions between Iranian authorities and the Arab minority over the last year.
Both attacks occurred far away from any oil facilities, where small bombs damaged 15 pipelines and one oil well in September.
There was no immediate claim of responsibility for the bombings, which were the latest in a string of attacks and violence this year in Khuzestan province, the heartland of Iran's oil industry.
Officials said the two blasts, ten minutes apart, shattered windows of the government buildings. "The bombs were hidden in the washrooms of the two buildings," a provincial official said. "The buildings were heavily damaged and are closed."
Khuzestan, which borders Iraq, contains most of Iran's Arabic-speaking minority.
Officials have blamed the violence on exile-based separatist groups and have accused Britain of stirring unrest in Khuzestan. London denies the charge.