A truck bomb exploded at Iraq's main commodities port near the oil-exporting southern city of Basra, wounding four people on Saturday, but officials said shipping traffic at the Umm Qasr docks was not affected.
Umm Qasr port, near Iraq's border with Kuwait, sits at the top of the strategic Gulf waterway and does not export oil. Imports handled there include grain shipments and heavy equipment used in the energy industry.
The blast damaged an out-of-service Iraqi ship anchored there and wounded four porters, the head of the Basra provincial security committee, Jabbar al-Saedi, told Reuters.
"It's a serious breach to the port security and a terrorist act targeting Iraq's economy," he said.
The truck had been parked near one of the port's unloading berths, he added.
Shipping movements and unloading operations at the port were not disrupted by the explosion, said Mahdi Askar, an official with the state-run General Company for Maritime Transport.
The site is close to the city of Basra, about 420 km (260 miles) southeast of the capital Baghdad.
Iraq's economic infrastructure has been hit hard by frequent militant attacks. An oil export pipeline between Iraq and Turkey has been bombed about 30 times since the start of the year, the oil ministry said last week. The pipeline was hit again late on Friday.
Sunni Muslim militant groups, including al-Qaida, have stepped up their insurgency against Iraq's Shi'ite-led government in the past four months.
More than 30 people were killed and scores wounded in Baghdad on Thursday after a series of car bombs, part of a wave of violence that has taken the monthly death toll to the highest levels in around five years.