TEHRAN, Iran (AP) - At least eight people were killed and 36 others injured Sunday in four bomb explosions that targeted government buildings and officials in southwestern Iran, state-run television reported. At least four women were among those killed in the explosions in Ahvaz, capital of the southwestern Khuzestan province which borders Iraq. The blasts were the deadliest explosions in Iran in more than a decade. Gholamreza Shariati, deputy provincial governor for security affairs, said perpetrators were seeking to undermine public participation in Friday's presidential elections. Television pictures showed the blast sites with heavily damaged buildings and blood on the ground. The force of the explosions also damaged cars in the streets. Shariati said 36 people, including eight police officers, were injured. Following the first three blasts, experts had tried to defuse a fourth bomb but failed, and it exploded. Ahvaz was the site of two days of violent demonstrations in April after reports circulated of an alleged plan to decrease the proportion of Arabs in the area. Officials at the time confirmed one death but opposition groups said more than 20 demonstrators had been killed. Some 250 were arrested. The protests were sparked after copies of a letter allegedly signed by Vice President Mohammad Ali Abtahi circulated in the area. The letter ordered the relocation of non-Arabs to the Ahvaz to make them the majority population. Abtahi denied writing the letter. Arabs make up about 3 percent of Iran's population, Persians account for 51 percent and other minorities comprise the remainder. Bomb explosions have been a rare occurrence in Iran since the end of the 1980-88 Iran-Iraq war.