The death toll from weekend explosions days before Iran's presidential election rose to 10 when one of the injured died, the official Islamic Republic News Agency reported Monday.
At least 98 people in provincial capital of Ahvaz (search) were wounded — 26 in serious condition, state-run radio quoted Gov. Mohammad Jafar Sarrami as saying. Ahvaz is the capital of oil-rich Khuzestan province, bordering Iraq.
The overnight death in the hospital brought the number killed in Sunday's bombings to 10 — nine in Ahvaz and one in Tehran. Another four were wounded in the Tehran blast. The bombings, which came ahead of Friday's election, were the deadliest in more than a decade in Iran.
Police said one suspect had been arrested, but did not give further details.
A spokesman for the Supreme National Security Council blamed groups affiliated with Saddam Hussein's former Baathist (search) regime in Iraq. State TV quoted spokesman Ali Agha Mohammadi as saying those behind the Ahvaz bombings had infiltrated Iran from Basra in southern Iraq.
Some Sunni leaders in Iraq have accused Shiite Iran of meddling in Iraqi affairs by backing Shiite Muslim clergy and politicians in a bid to sway Iraq's politics toward an Islamic establishment.
Iran denies the allegations, but some speculate that Saddam loyalists could be trying to create insecurity in Iran ahead of the election.
Others pointed to a more local cause. Ahvaz was the site of recent violent protests over alleged plans to alter the proportion of Arabs and non-Arabs in the region.
Amir Hossein Motahar, director of security at the Interior Ministry, said one car bomb went off in front of the Ahvaz governor's office. He said two separate bombs blew up in the city's housing department and planning department. The fourth bomb, planted in a handbag on the street, exploded as experts tried to defuse it. The fourth site was near the home of the head of the provincial radio and television station.
The two days of violent protests in Ahvaz took place 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 (search) 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 of the population of 69 million.
Bombings have been rare in Iran since the end of the 1980-88 war with Iraq.