An explosion rocked an area near a Jiddah branch of the Saudi-American bank today, according to early reports.
An Arab TV station said one attacker was wounded and others are holed up in a nearby house.
An official at the bank said an explosion took place in the al-Bawadi district of Jiddah, a Red Sea port in the west of the kingdom where the bank has a branch.
Saudi-owned Al-Arabiya TV said the explosion happened outside the branch.
The official said that the explosion had not affected the bank’s operations and gave no further details.
The blast came on the third anniversary of the September 11 attacks in the United States, which were carried out by 19 Arab militants, including 15 Saudis, and blamed on the al-Qaida terror network headed by Saudi-born Osama bin Laden.
The US Embassy spokeswoman in the Saudi capital Riyadh, Carol Kalin, said she was investigating the report but was unable to confirm if there had been an explosion.
Saudi security officials were not immediately available for comment, while bank employees refused to speak about the report.
Al-Arabiya said in a further report that an attacker was wounded and taken to hospital where he is reportedly under close guard.
Several other militants fled the scene in a stolen vehicle to a neighbourhood where the US consulate is located and took shelter in an uninhabited house about 700 yards from the consulate. About 200 police have sealed the area off.
Saudi Arabia has been hunting al-Qaida-linked militants behind a series of bombings and shootings in the Gulf kingdom that have targeted the US-allied Saudi regime, security authorities and foreign interests.