Suicide bombers in two cars killed 26 people and wounded 53 in the Iraqi capital Baghdad yesterday when they drove down a crowded street and blew themselves up simultaneously, security officials said.

The bombers targeted the Baghdad branch of the Trade Bank of Iraq, the conduit for much of the government's foreign exchange transactions and its dealings with investors.

The bank is on a busy thoroughfare through the mainly Sunni Arab district of Mansur that provides access from western Iraq to the fortified Green Zone government and embassy compound in the city centre.

The morning attack came just a week after five suicide bombers stormed the Central Bank of Iraq killing 18 people during a four-hour siege and underlined the dangers of a resurgence of violence in the face of a persistent political vacuum more than three months after a general election.

"The report of the bomb disposal team confirmed that the two attacks that happened in Mansur today were carried out by suicide bombers who drove the car bombs," Baghdad's operations command said.

"Each car was loaded with 80 kilogrammes of ammonium nitrate," the command said in a statement. "They were detonated simultaneously. They targeted the Trade Bank of Iraq."

Five of the branch's guards were among the dead and six among the wounded, TBI chairman Hussein al-Uzri said, adding the "cowardly attack" would not prevent the bank opening for business as usual today.

"This attack on our headquarters in Baghdad... was an act of cowardice by malevolent forces who wish to undermine the progress that Iraq is steadily making towards stability, peace and economic prosperity for all its people," Mr Uzri said in a statement.

"However, this cowardly attack was a failure. The Trade Bank of Iraq, and Iraq itself, are undeterred," he said.