Saudi security forces are reported to be fighting to regain control of the compound, and flames and smoke can be seen rising from the compound.

Witnesses said a car exploded in the street outside the consulate before the attackers entered the compound.

Security sources quoted by Reuters say four Saudi guards were killed and 18 local staff taken hostage.

There are no reports of American casualties.

About 200 Saudi police and National Guard soldiers are reported to have been deployed in the area, which has been sealed off.

Correspondents say security around the consulate has been extremely tight since a series of bombings by Islamist militants in Saudi Arabia in 2003, mainly targeting buildings that house foreigners.

The US embassy in the capital, Riyadh, and another consulate in the eastern city of Dhahran have also been closed as a precaution, a US spokeswoman said.

Prometheus Institute does not endorse any article or comment that is published on PEJ.org. The opinions expressed in all articles and comments are those of the authors and not of Prometheus Institute or the Peace, Earth & Justice News.